The results of this analysis suggest that, on a typical day 

in 2004, there were an estimated 3.8 million nonimmigrants in the United States, including 2.3 million tourists, 

business travelers, and other short-term visitors, 704,000 

temporary workers, 640,000 students and exchange 

visitors, and 68,000 diplomats and other representatives. 

Approximately 841,000 were land border crossers from 

Canada and Mexico. The countries with the highest number 

of nonimmigrants were Mexico (889,000) and Canada 

(572,000), followed by India (303,000), the United 

Kingdom (228,000), and Japan (196,000). 

ESTIMATING THE SIZE OF THE 

NONIMMIGRANT POPULATION

On any day of the year, the nonimmigrant population, 

including tourists, diplomats, students, and temporary 

workers, represents a significant portion of the foreignborn population present in the United States. Estimates of 

the size of the total foreign-born population are available 

from the decennial census and other federal surveys, 

such as the American Community Survey (ACS) and the 

Current Population Survey (CPS). However, estimates of 

the nonimmigrant population cannot be obtained 

directly from census, ACS, or CPS data, primarily 

because federal surveys do not include a question on 

the legal status of foreign-born non-citizens. Also, 

because the universe for many federal surveys, including 

the decennial census and the ACS, is the resident population, 

they likely capture many nonimmigrants who reside in 

the United States for extended periods but fail to 

enumerate the majority of nonimmigrants, such as tourists 

and business travelers, who remain in the country for 

short periods of time.

Because of the limitations associated with the available 

census and survey data, this paper uses administrative 

flow data and a “person year” methodology to estimate 

the size of the nonimmigrant population. In general, 

the person year population estimate is calculated by 

multiplying the number of nonimmigrant admissions 

Office of Immigration Statistics

POLICY DIRECTORATE

JUNE 2006 Population EstimatesEstimates of the Nonimmigrant 

Population in the United States: 2004

ELIZABETH M. GRIECO

This Office of Immigration Statistics Population Estimates report presents estimates of the nonimmigrant 

population in the United States in 20041. (For a definition of the term “nonimmigrant,” see Box 

1.) The estimates were based primarily on data from the Department of Homeland Security’s 

Nonimmigrant Information System (NIIS)2. Stock estimates for the total nonimmigrant population 

by category of admission and country of citizenship were generated using this administrative flow 

data and a “person year” methodology.3

1 In this report, years refer to fiscal years (the 12 month period ending September 

30 of the year designated).

2 During the first quarter of fiscal year 2005, NIIS was incorporated into Customs 

and Border Protection’s Treasury Enforcement Communications System (TECS) and 

is no longer operated as an independent system.

3 The person year methodology used in this report is based on previous work by 

Michael Hoefer (personal communication).

Box 1. 

Defining “Nonimmigrant”

A nonimmigrant is a foreign national seeking to enter 

the United States temporarily for a specific purpose. 

Nonimmigrants are admitted for a temporary period of 

time and, once in the country, are restricted to the activity 

or reason for which their visa was issued. They may have 

more than one type of nonimmigrant visa but are admitted 

in only one status.

In general, foreign nationals seeking temporary admission to the United States must first apply for a visa at the 

American Embassy or Consulate with jurisdiction over 

their place of permanent residence. The type of nonimmigrant visa required is defined by immigration law and 

relates to the purpose of travel. Visa applicants must also: 

be admissible or have obtained a waiver for any ground 

of inadmissibility; be in possession of a valid passport; 

maintain a foreign residency, in most instances; show 

proof of financial support for their stay, if required; abide 

by the terms and conditions of admission; and agree to 

depart at the end of their authorized stay or extension.
2 DHS Office of Immigration Statistics

in a given year by the mean length of visit (i.e., the average 

number of days spent per trip by a nonimmigrant admitted to the 

United States). The person year estimate accounts for the portion 

of the year that, on average, each nonimmigrant admitted 

remained in the country. For example, if six nonimmigrants 

arrived and remained on average for two months, then their visits, 

when combined, would make one person year of continued presence. 

This single person year, representing six admissions, would count 

as one person in the population estimates. Multiplying the total 

number of admissions that occurred within a given year by the 

mean length of visit produces an estimate of the total number of 

days spent in the country by all nonimmigrants. Dividing this 

product by 365 results in a per day estimate, which is interpreted 

as the size of the nonimmigrant population in the country on a 

typical day of the year.

Interpreting the Person Year Estimates. The nonimmigrant 

population estimates calculated using the person year methodology 

represent the size of the population on a typical day of the year. 

Because the estimates are a composite measure based on data from 

an entire year, they do not represent the size of the population on 

a specific reference day (e.g., the beginning, middle, or end of the 

year), but rather the average population size for all days throughout 

the year. The person year methodology produces estimates – not 

actual counts – of the size of the nonimmigrant population present 

in the United States. 

Data

Nonimmigrant Information System. The primary source of data 

on nonimmigrant admissions into the United States is the Nonimmigrant Information System (NIIS). NIIS compiles and maintains 

information collected from nonimmigrants on DHS Form I-94, also 

known as the Arrival-Departure Record, which asks for dates of 

arrival and departures as well as limited demographic information, 

such as name, sex, nationality, and date of birth. Nonimmigrants 

arriving by air, land, or sea are required to complete Form I-94, 

with two important exceptions. Canadians who travel to the United 

States as tourists or on business generally do not need the I-94 

Form.4 Also, certain Mexicans who have a nonresident alien Border 

Crossing Card, commonly known as a laser visa, may not require 

the I-94 Form for entry.5 These exceptions are significant because 

Canadian and Mexican citizens make up the vast majority of all nonimmigrant admissions. While NIIS excludes the majority of short-term 

admissions from Canada and Mexico, it does capture short-term 

admissions, including tourists, business travelers, and transit aliens, 

from all other countries. NIIS also captures temporary residents, 

such as students and high-skilled workers, long-term residents, such 

as fiancés(ées) of U.S. citizens, and diplomats, such as ambassadors 

and consular officers, from all countries, including Canada and Mexico. 

Performance Analysis System. A second administrative source, 

the Performance Analysis System (PAS), was used to estimate the 

number of nonimmigrants admitted from Canada and Mexico 

who were not required to complete Form I-94. PAS is the principal 

data entry and retrieval system for the G-22/23 Report of Field 

Operations. The G-22/23 report includes a variety of immigrationrelated operational workload measures, such as port-of-entry arrival 

inspections, immigrant status adjudications, and naturalizations. 

Unlike NIIS, however, PAS does not include the nonimmigrants’ 

class of admission, date of arrival and departure, or any demographic 

characteristics. For this report, the G-22.1 Inspection Report was 

used to estimate the total (i.e., aggregate) number of nonimmigrant 

admissions as well as the proportion of those admissions that 

occurred at either the northern or southern land border. 

Assumptions and Limitations

The person year methodology assumes that the arrival data accurately 

capture the number of nonimmigrants who come to the United States 

and the departure data capture the length of time they spend in 

each class of admission. These assumptions are most likely violated 

for those nonimmigrant classes that commonly change status 

while in the country, either to another nonimmigrant or legal 

permanent resident status, since changes in status are not captured 

by the arrival-departure record. Because temporary workers, 

students and exchange visitors, and especially expected long-term 

residents commonly change status while in the United States, the 

population estimates generated by the person year methodology 

for these categories of admission are likely understated. The 

impact of change of status on the estimates of the temporary 

resident population will be further investigated by OIS. 

RESULTS

Data Presentation

This report uses five broad categories of admission to present the 

results of the analysis, including 1) tourists, business travelers, and 

other short-term visitors, 2) students and exchange visitors, 3) 

temporary workers, 4) diplomats and other representatives, and 5) 

expected long-term residents. These five categories group admissions 

based on both type and authorized/initial period of stay.

Tourists, business travelers, and other short-term visitors include 

nonimmigrants who remain in the United States for short periods, 

typically for a few days to a few weeks.6 Students and exchange 

visitors, including researchers, usually remain in the country for 

several months to several years. Nonimmigrants who come to the 

United States to work for a few months to several years are included 

in the temporary workers category. Diplomats and representatives 

of international organizations typically remain in the United States 

for the duration of their service. The expected long-term residents 

category includes those who arrived on nonimmigrant visas but 

4 Canadian citizens crossing the border for business or pleasure can remain in the United States 

without a visa for up to one year.

5 Mexican citizens entering the United States as tourists or business travelers require either a 1) 

Border Crossing Card (BCC) or 2) B-1 business or B-2 tourist nonimmigrant visa and a passport. 

Mexican citizens who have obtained a BCC and who wish to enter the United States and remain 

within 25 miles of the border (or within 75 miles of the border of Arizona) for 30 days or less are 

not required to complete an I-94 Form. Mexican citizens with a nonimmigrant visa and passport who 

wish to enter and remain within 25 miles of the border for 72 hours or less are also not required to 

complete an I-94 Form. Mexican citizens with either a BCC or a nonimmigrant visa and passport 

who wish to stay longer or go farther than these limits would be required to complete an I-94 Form. 

All I-94 Forms issued at land borders are for multiple entries unless specifically annotated for a 

limited number of entries.

6 Tourists, business travelers, and other short-term visitors also include transit aliens – foreign 

nationals in immediate and continuous transit through the United States to foreign destinations 

and to and from the United Nations headquarters district in New York City.
DHS Office of Immigration Statistics 3

are likely to become permanent residents, such as certain spouses 

and fiancés(ées) of U.S. citizens.7

Nonimmigrant Admissions in 2004

According to PAS, there were a total of 180.2 million nonimmigrant 

admissions8 into the United States in 2004 (see Table 1). Of those, 

30.8 million were issued an I-94 and were captured by NIIS.9

The majority of the 180.2 million admissions were by tourists, business travelers, and other short-term visitors (177.1 million), followed 

by temporary workers (1.5 million), students and exchange visitors 

(1.0 million), diplomats and other representatives (277,000), and 

expected long-term residents (105,000) (see Table 2). 

The countries with the highest number of admissions were Mexico 

(111.2 million) and Canada (42.9 million), followed by the 

United Kingdom (5.0 million), Japan (4.3 million), and Germany 

(1.6 million) (see Table 3). 

Estimating Admissions from Canada and Mexico. There were 

an estimated 154.1 million admissions from Canada and Mexico 

combined, including 149.4 million admissions recorded by PAS and 

4.7 million admissions recorded by NIIS. Because PAS does not include 

information on the country of origin, the number of admissions 

from either Canada or Mexico was estimated using information 

from PAS on land admissions at the northern or southern borders. 

In 2004, 29 percent of all land border admissions occurred at the 

northern border while 71 percent occurred at the southern border. 

This percent distribution suggests that, of the total 149.4 million 

admissions recorded by PAS, 42.6 million were admitted from 

Canada and 106.8 million were admitted from Mexico.10

Of the 111.2 million admissions from Mexico, the estimated 106.8 

million admissions recorded by PAS were land border admissions, 

including all BCC and B-1 (business traveler)/B-2 (tourist) visa plus 

passport admissions. An I-94 Form is required for all air and sea 

admissions from Mexico, plus some land admissions. Of the 4.5 million 

admissions from Mexico recorded by NIIS, 2.5 million were land 

admissions. Combined, the PAS and NIIS data suggest there were an 

estimated 109.3 million land border admissions from Mexico in 2004.

Unfortunately, the Canadian PAS admissions data cannot easily be 

disaggregated by mode of transportation. Of the 42.9 million 

admissions from Canada, the estimated 42.6 million admissions 

recorded by PAS include visa exempt tourist and business travelers 

arriving by land, air, and sea. To estimate the number of admissions 

by land, the percent distribution of Canadian residents returning 

to Canada from the United States by mode of transportation was 

derived from Statistics Canada’s International Travel Survey. The 

Table 1.

Nonimmigrant Admissions to the United States: 

Fiscal Year 2004 (in thousands)

Category

Admissions

Number Percent

 Total1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Admissions issued an I-94 Form at entry . . . . . . . . . . .

All other admissions2. . . . . . . . . . . . . . . . . . . . . . . . . .

180,187

30,781

149,406

100.0

17.1

82.9

1 The 180.2 million nonimmigrant admissions for fiscal year 2004 exclude sea and air crew admissions (D-1 and D-2 visas).

2 Includes an indeterminate number of second and subsequent entries by nonimmigrants who were 

admitted using a multiple-entry I-94 Form at a land border crossing.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival 

File, FY 2004 and the Performance Analysis System (PAS).

7 The categories students and exchange visitors, temporary workers, diplomats and other representatives, and expected long-term residents include principals, spouses, and children.

8 The 180.2 million nonimmigrant admissions for fiscal year 2004 exclude sea and air crew admissions (D-1 and D-2 visas) but include the 30.8 million nonimmigrant admissions recorded by NIIS.

9 The 30.8 million admissions captured by NIIS exclude an indeterminate number of second and 

subsequent entries by nonimmigrants who were admitted using a multiple-entry I-94 Form at a land 

border crossing.

10 For this report, it is assumed that the 42.6 million admissions from Canada were Canadian 

citizens and the 106.8 million admissions from Mexico were Mexican citizens. However, the PAS 

admissions include an indeterminate number of second and subsequent entries by nonimmigrants 

from countries other than Canada and Mexico who were admitted using a multiple entry I-94 Form 

at a land border crossing.

Table 2.

Nonimmigrant Admissions to the United States by Category of 

Admission: Fiscal Year 2004 (in thousands)

Category of admission

Admissions

Number Percent

 Total1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tourists, business travelers, and other short-term visitors2 . . .

Students and exchange visitors . . . . . . . . . . . . . . . . . .

Temporary workers . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diplomats and other representatives . . . . . . . . . . . . . .

Expected long-term residents . . . . . . . . . . . . . . . . . . . .

Unknown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

180,187

177,140

1,017

1,517

277

105

131

100.0

98.3

0.6

0.8

0.2

0.1

0.1

1 The 180.2 million nonimmigrant admissions for fiscal year 2004 excludes sea and air crew admissions (D-1 and D-2 visas). 

2 Includes transit aliens. Also includes an indeterminate number of second and subsequent entries 

by nonimmigrants who were admitted using a multiple-entry I-94 Form at a land border crossing.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival 

File, FY 2004 and the Performance Analysis System (PAS).

Table 3.

Nonimmigrant Admissions to the United States by Country 

of Origin: Fiscal Year 2004 (in thousands)

Country of origin

Admissions

Number Percent

 Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mexico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Land border crossers1 . . . . . . . . . . . . . . . . . . . . . . .

 Other. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Land border crossers2 . . . . . . . . . . . . . . . . . . . . . . .

 Other. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

United Kingdom . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Germany. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Korea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Italy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Australia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

India . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

All other countries . . . . . . . . . . . . . . . . . . . . . . . . . . . .

180,187

111,231

109,253

1,978

42,867

37,183

5,685

4,996

4,336

1,630

1,242

829

760

645

611

11,039

100.0

61.7

60.6

1.1

23.8

20.6

3.2

2.8

2.4

0.9

0.7

0.5

0.4

0.4

0.3

6.1

1 Includes an indeterminate number of second and subsequent entries by nonimmigrants from countries 

other than Mexico who were admitted using a multiple-entry I-94 Form at a land border crossing.

2 Includes an indeterminate number of second and subsequent entries by nonimmigrants from countries 

other than Canada who were admitted using a multiple-entry I-94 Form at a land border crossing.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival 

File, FY 2004 and the Performance Analysis System (PAS).
4 DHS Office of Immigration Statistics

data suggest that, of the 42.6 million admissions recorded 

by PAS, 37.1 million (87 percent) arrived by land, 

5.4 million (13 percent) arrived by air, and 171,000 

(less than one-half of 1 percent) arrived by sea. Certain 

nonimmigrants from Canada are required to complete 

an I-94 Form when they enter the United States. Of the 

239,000 admissions recorded by NIIS, 96,000 were land 

admissions. Combined, the PAS and NIIS data suggest 

there were an estimated 37.1 million land border admissions from Canada in 2004.

Mean Length of Visit

In this report, the term visit refers to the time between a nonimmigrant’s entry and departure. Note that the term visit 

refers to the trip, not the traveler. A tourist, for example, who 

came to the United States during a year for a four-week 

vacation made a single visit. A business traveler who made 

three one-week trips during the same year made three visits. 

Length of visit was calculated by subtracting the date 

of departure in 2004 from the date of arrival. Same 

day departures were represented as one day.

The mean length of visit represents the average 

number of days spent per trip by a nonimmigrant 

admitted to the United States. For the majority 

of admissions issued an I-94 Form at entry, the 

average length of visit was calculated from 

matched arrival and departure records in NIIS. 

Nonimmigrant departure records were matched to 

arrival records using three criteria: the admission 

number included on the arrival and departure 

portions of the I-94 Form, the first letter of the 

nonimmigrant’s last name, and the nonimmigrant’s 

date of birth. Departures that occurred in 2004 

were matched to arrivals that occurred between 

2000 and 2004. Of the 26.4 million departures 

recorded by NIIS in 2004, 24.9 million or 94 percent 

were matched to arrival records (see Table 4). 

In general, most of the matched arrivals and departures used to estimate 

the mean length of visit occurred within the same year. Over 91 percent 

of all departures that occurred in 2004 were matched to arrivals that 

also occurred in 2004 (see Table 5). Thus, the mean length of visit used 

to calculate the nonimmigrant population estimates represents the actual 

arrival and departure behavior of 2004 admissions. However, the proportion of matched arrivals and departures where both the arrival and 

departure occurred in 2004 varies considerably by broad category of 

admission. Tourists, business travelers, and other short-term visitors 

(94 percent) had the highest proportion, followed by diplomats and 

other representatives (79 percent), temporary workers (64 percent), 

students and exchange visitors (48 percent) and expected long-term 

residents (34 percent). For categories of admission with lower 

percentages of matched arrival and departures both occurring in 2004, 

such as temporary workers and students and exchange visitors, the mean 

length of visit reflects the arrival and departure behavior of admissions 

that occurred in 2004 as well as those that occurred in earlier years.

Also, for arrivals without matching departure records, it was 

assumed that the mean length of visit was the same for nonimmigrants in the same class of admission whose arrival and departure 

records could be matched. Of the 30.8 million nonimmigrant 

admissions in 2004, 22.7 million were matched to departures that 

occurred in 2004, leaving 8.1 million unmatched arrival records.11

The means derived from the matched arrival and departure 

records were used to estimate the lengths of visit of the 8.1 million 

unmatched admissions.

The majority of nonimmigrants issued an I-94 Form at entry 

remained in the United States for one year or less per visit. 

Table 5.

Nonimmigrant Departures Matched to Nonimmigrant Arrivals (Form I-94 Admissions 

Only) by Category of Admission and Year of Arrival: Fiscal Year 2004 (in thousands)

Category of admission

Departures in 2004

Total

Year of arrival

2004 2000 to 2003

Number Percent Number Percent

 Total. . . . . . . . . . . . . . . . . . . . . . . . . 

Tourists, business travelers, and other

 short-term visitors1. . . . . . . . . . . . . . . . 

Students and exchange visitors . . . . . . . . 

Temporary workers . . . . . . . . . . . . . . . . . 

Diplomats and other representatives . . . . 

Expected long-term residents . . . . . . . . . . 

Unknown . . . . . . . . . . . . . . . . . . . . . . . . 

24,901

22,648

773

1,126

229

31

93

22,724

21,358

374

718

181

10

83

91.3

94.3

48.3

63.8

78.8

33.7

89.0

2,177

1,291

399

408

49

21

10

8.7

5.7

51.7

36.2

21.2

66.3

11.0

1 Includes transit aliens.

Note: Departures occurred during fiscal year 2004 and were matched to arrivals that occurred between fiscal year 2000 and 2004.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival and Departure Files, FY 2004.

Table 4.

Nonimmigrant Departures Matched to Nonimmigrant Arrivals (Form I-94 

Admissions Only) by Category of Admission: Fiscal Year 2004 (in thousands)

Category of admission

Departure records

Number

Matched 

to arrival 

records1

Percent 

matched

 Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tourists, business travelers, and other 

 short-term visitors2. . . . . . . . . . . . . . . . . . . . . . . . . .

Students and exchange visitors . . . . . . . . . . . . . . . . . .

Temporary workers . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diplomats and other representatives . . . . . . . . . . . . . .

Expected long-term residents . . . . . . . . . . . . . . . . . . . .

Unknown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

26,394

23,872

863

1,197

241

34

188

24,901

22,648

773

1,126

229

31

93

94.3

94.9

89.6

94.1

95.3

90.2

49.6

1 Includes only those matched records with valid dates of arrival and departure.

2 Includes transit aliens.

Note: Departures occurred during fiscal year 2004 and were matched to arrivals that occurred between fiscal year 

2000 and 2004.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival and Departure 

Files, FY 2004.

11 The majority of the 8.1 million unmatched arrivals consist of nonimmigrants who, as of the end 

of fiscal year 2004, had not yet departed. It also includes arrivals that were not matched because 

the departures were not recorded by the NIIS data system, primarily because I-94 Forms are not 

always collected when nonimigrations leave the United States. This would occur, for example, if an 

airline failed to collect the I-94 Form from departing air passengers or if nonimmigrants leave via 

land ports where there are less structured procedures to collect the forms. The exact number of 

uncollected departure forms is not known.
DHS Office of Immigration Statistics 5

Approximately 99 percent who departed in 2004 had stayed for 

one year or less (see Table 6). Overall, less than 2 percent of nonimmigrants remained for more than one year per visit, but this 

proportion varied considerably by category of admission. Expected 

long-term residents (30 percent) had the highest proportion staying 

more than one year, followed by students and exchange visitors 

(15 percent), temporary workers (11 percent), diplomats and 

other representatives (5 percent), and tourists, business travelers, 

and other short-term visitors (less than one-half of 1 percent).

Mean Length of Visit for Nonimmigrant Admissions from 

Canada and Mexico. Because the dates of admission and departure 

of nonimmigrant arrivals are not collected by PAS, the mean length 

of visit for the majority of nonimmigrant admissions from both 

Canada and Mexico was estimated from other sources. For Canadian 

admissions, data from Statistics Canada’s International Travel Survey on the length of stay of Canadian 

citizens returning from the United States were 

used to estimate mean length of visit of air, land, 

and sea admissions.12

For Mexican land border crossers, the data used to 

estimate mean length of visit were derived from a 

study on the economic impact of Mexican visitors 

from Arizona.13 The study estimates that, in 2001, 

over 96 percent of all Mexican visitors were daytrip visitors, with approximately 0.8 percent 

spending one night, 1.9 percent spending two 

nights, and 1.2 percent spending three or more 

nights. This suggests a mean length of visit of 1.1 

days for Mexican border crossers.14 Although the 

results of this study are specific to Arizona, for 

generating the nonimmigrant estimates presented 

in this report, it is assumed that the behavior of the Mexican land 

border crossers going to Arizona is the same as all Mexican land 

border crossers. It is also assumed that the mean length of visit 

calculated has not changed since 2001.

Mean Length of Visit by Broad Category of Admission. On 

average, tourists, business travelers, and other short-term visitors 

who were required to complete an I-94 Form when admitted into 

the United States remained in the country for 22 days (see Table 7). 

The average length of visit for admissions from Canada 

(excluding I-94 admissions) was just under four days, but this 

varies by mode of transportation. Nonimmigrants arriving by air 

from Canada remain an average of nine days, while those arriving 

by sea remain for about eight days and by land for three days. Land 

border crossers from Mexico remain for just over one day per visit. 

Diplomats and other representatives stayed for about 13 weeks 

(88 days) per visit, while temporary workers remain for 23 weeks 

(158 days), students and exchange visitors for 31 weeks (219 days), 

and expected long-term residents for 43 weeks (302 days).

Calculating the Population Estimates

For nonimmigrants required to complete an I-94 Form, the population estimates were calculated by multiplying the number of 

admissions by the mean length of visit for each class of admission 

and country of citizenship group then dividing by 365. For example, 

the number of B-2 tourist admissions from France was multiplied 

by the mean length of visit of B-2 tourists from France then 

divided by 365. If the mean length of visit could not be calculated 

by the country-specific class of admission, then the mean for the 

total class of admission was used.

For Canadian and Mexican I-94 admissions, the population estimates 

were calculated using class of admission, country of citizenship, 

Table 6.

Nonimmigrant Departures Matched to Nonimmigrant Arrivals (Form I-94 Admissions 

Only) by Category of Admission and Length of Visit: Fiscal Year 2004 (in thousands)

Category of admission Number

Length of visit

One year or less More than one year

Number Percent Number Percent

 Total. . . . . . . . . . . . . . . . . . . . . . . . . 

Tourists, business travelers, and other

 short-term visitors1. . . . . . . . . . . . . . . . 

Students and exchange visitors . . . . . . . . 

Temporary workers . . . . . . . . . . . . . . . . . 

Diplomats and other representatives . . . . 

Expected long-term residents . . . . . . . . . . 

Unknown . . . . . . . . . . . . . . . . . . . . . . . . 

24,901

22,648

773

1,126

229

31

93

24,562

22,572

659

1,001

217

22

91

98.6

99.7

85.3

88.9

94.7

70.2

97.9

339

77

114

125

12

9

2

1.4

0.3

14.7

11.1

5.3

29.8

2.1

1 Includes transit aliens.

Note: Departures occurred during fiscal year 2004 and were matched to arrivals that occurred between fiscal year 2000 and 2004.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival and Departure Files, FY 2004.

Table 7.

Length of Visit of Nonimmigrants by Category of Admission: 2004

Category of admission

Mean 

length 

of visit1

Tourists, business travelers, and other short-term visitors

 I-94 Admissions2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Admissions from Canada3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Land . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Sea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Land border admissions from Mexico3,4 . . . . . . . . . . . . . . . . . . . . . . .

Students and exchange visitors . . . . . . . . . . . . . . . . . . . . . . . . . . .

Temporary workers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diplomats and other representatives . . . . . . . . . . . . . . . . . . . . . . .

Expected long-term residents . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unknown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

22.0

3.7

9.0

3.0

7.8

1.1

219.1

157.6

87.8

301.7

42.7

1 Same-day departures are represented as one day.

2 Includes transit aliens.

3 Includes all nonimmigrant admissions not required to complete an I-94 Form upon entry and an 

indeterminate number of second and subsequent nonimmigrant entries who were admitted using a 

multiple-entry I-94 Form at a land border crossing. 

4 Mean length of visit for 2001.

Source: Statistics Canada, International Travel Survey, special tabulation; Charney and Pavlakovich 

(2002); and U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival 

and Departure Files, FY 2004 and the Performance Analysis System (PAS).

12 Statistics Canada, International Travel Survey, special tabulation.

13 See Charney, Alberta and Vera Pavlokovich-Kochi, 2002, “The Economic Impacts of Mexican Visitors to Arizona: 2001,” University of Arizona, Karl Eller College of Business and Public Administration. A copy of this report is available at http://ebr.eller.arizona.edu/research/MexicanVisitors.pdf.

14 Assuming a value of 1 for same-day visits, 2 for visits of one night, 3 for visits of two nights, and 

4 for visits of three or more nights, ((96.1*1)+(0.8*2)+(1.9*3)+(1.2*4))/100 = 1.1 days.
6 DHS Office of Immigration Statistics

and mode of transportation. For air and sea admissions, the population 

estimates were calculated by multiplying the number of admissions 

in each class by the mean length of visit for that class. For land 

admissions, however, an additional adjustment was required. All 

I-94 Forms issued at land border crossings are valid for 180 days 

and for multiple entries. However, only the first entry date (when 

the I-94 Form was issued) and the last departure date are recorded 

by NIIS, regardless of the number of entries that occurred during 

the six-month period. For I-94 land admissions, it is probable that 

the departure record is collected when the form itself has expired 

and not at the first departure after initial arrival. To compensate, 

the means by class of admission for air arrivals were used in place 

of those for land arrivals.

For Canadian and Mexican nonimmigrants not required to complete an I-94 Form at entry, the person year estimates were derived 

by multiplying the number of admissions by the mean lengths of 

visit derived from other data sources.

Nonimmigrant Population Estimates

On a typical day in 2004, there were 3.8 million nonimmigrants 

in the United States (see Table 8). Approximately 2.3 million 

(61 percent) were tourists, business travelers, and other shortterm visitors, while 704,000 (18 percent) were temporary workers 

and 640,000 (17 percent) students and exchange visitors. Combined, 

the remaining categories of admission accounted for less than 

5 percent of the nonimmigrant population, including 71,000 

expected long-term residents (1.9 percent) and 68,000 diplomats 

and other representatives (1.8 percent).

Nonimmigrant Population Estimates by Country of Citizenship. 

Among the 3.8 million nonimmigrants in the United States on a 

typical day in 2004, about 889,000 (23 percent) were from Mexico 

while 572,000 (15 percent) were from Canada (see Table 9). Six 

additional countries represented over 2 percent each of the nonimmigrant population, including India (7.9 percent), the United 

Kingdom (6.0 percent), Japan (5.1 percent), Korea (3.7 percent), 

Germany (2.9 percent), and China (2.4 percent).

Of the 3.8 million nonimmigrants, an estimated 841,000 (22 percent) 

were land border crossers, including 491,000 (13 percent) from 

Mexico and 350,000 (9 percent) from Canada. Of the 841,000 

land border crossers, 58 percent were from Mexico and 42 percent 

from Canada. 

NEXT STEPS

Estimates of the nonimmigrant population are updated annually 

by the Office of Immigration Statistics. The assumptions underlying 

the estimates will be reevaluated and revised as appropriate. Future 

research by the OIS will focus on refining the nonimmigrant 

estimates, focusing on the influence of change of status and other 

factors on the estimates of the temporary resident population.

SUGGESTED READINGS

Grieco, Elizabeth M., May 2005, “Temporary Admissions of 

Nonimmigrants to the United States in 2004,” Annual Flow Report,

Office of Immigration Statistics, Department of Homeland Security. 

A copy of this report is available at http://uscis.gov/graphics/shared/

statistics/publications/FlowRptTempAdmis2004.pdf.

Grieco, Elizabeth M., March 2005, “Length of Visit of Nonimmigrants Departing the United States in 2003,” Working Paper, Office 

of Immigration Statistics, Department of Homeland Security. 

A copy of this report is available at http://uscis.gov/graphics/shared/

statistics/publications/LengthVstNonim2003.pdf.

FOR MORE INFORMATION

Visit the Office of Immigration Statistics web page at http://www.

dhs.gov/immigrationstatistics or http://uscis.gov/graphics/shared/statistics.

Table 9.

Estimated Nonimmigrant Population in the United States by 

Country of Origin: Fiscal Year 2004 (in thousands)

Country of origin

Population 

estimate

Number Percent

 Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Mexico . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Land border crossers . . . . . . . . . . . . . . . . . . . . . . . .

 Other. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Canada . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

 Land border crossers . . . . . . . . . . . . . . . . . . . . . . . .

 Other. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

India . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

United Kingdom . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Japan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Korea1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Germany. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

China . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

France . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Taiwan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

All other countries . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3,820

889

491

398

572

350

222

303

228

196

142

109

93

64

50

1,175

100.0

23.3

12.9

10.4

15.0

9.2

5.8

7.9

6.0

5.1

3.7

2.9

2.4

1.7

1.3

30.8

1 Korea includes both North and South Korea.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival 

and Departure Files, FY 2004 and the Performance Analysis System (PAS).

Table 8.

Estimated Nonimmigrant Population in the United States by 

Category of Admission: Fiscal Year 2004 (in thousands)

Category of admission

Population 

estimate

Number Percent

 Total. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tourists, business travelers, and other short-term visitors1 . . .

Students and exchange visitors . . . . . . . . . . . . . . . . . .

Temporary workers . . . . . . . . . . . . . . . . . . . . . . . . . . .

Diplomats and other representatives . . . . . . . . . . . . . .

Expected long-term residents . . . . . . . . . . . . . . . . . . . .

Unknown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3,820

2,324

640

704

68

71

14

100.0

60.8

16.7

18.4

1.8

1.9

0.4

1 Includes transit aliens.

Source: U.S. Department of Homeland Security, Nonimmigrant Information System (NIIS), Arrival 

and Departure Files, FY 2004 and the Performance Analysis System (PAS).