LARGE RIVERS 

OF THE UNITED STATES 

Large Rivers 

of the United States 

By Kathleen T. lseri and W. B. Langbein 

GEOLOGICAL SURVEY CIRCULAR 686 

1974 
United States Department of the ·Interior 

ROGERS C. B. MORTON, Secretary 

Geological Survey 

V. E. McKelvey, Director 

first printing 197 4 

Second printing 1975 

Free on application to the U.S. Geological Survey, National Center, Reston, Va. 22092 
CONTENTS 

Page 

Abstract. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Measurement of discharge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Mississippi River system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

Base periods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Names of rivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Summary.............................................................. 5 

Additional information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

ILLUSTRATIONS 

Page 

Figure 1. Photograph showing suspended stream-gaging car, Mississippi River at St. Louis, Mo. . . . . . . . . • . . . . . . . . . . . . . . . . 2 

2. Photograph of truck and equipment used in obtaining streamflow measurements from a bridge . . . . . . . . . . . . . . . . . 2 

J. Photograph showing hydrologists obtaining streamflow measurements from a moving boat . . . . . . . . . . . . . . . . . . . . 3 

4. Map showing large rivers in the United States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

TABLES 

Page 

Table 1. Average discharge at downstream gaging stations on large rivers of the United States, 1931-60 and 1941-70 . . . . . . . S 

2. Large rivers in the United States in order of average discharge at mouth, 1931-60, 1941-70. Order 

based on average discharge for 1941-70 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

III 

Large Rivers of the United States 

By Kathleen T. lseri and W. B. Langbein 

ABSTRACT 

Information on the flow of the 28 largest rivers in the United 

States is presented for the base periods 1931-60 and 1941-70. 

Drainage area, stream length, source, and mouth are included. 

Table 1 shows the average discharge at downstream gaging stations. Table 2 lists large rivers in order of average discharge at the 

mouth, based on the period 1941-70. 

INTRODUCTION 

Everyone knows that the Mississippi River is the largest river in the United States. But what rivers are the 

second and third largest? To compare the size of rivers, 

one must know what is meant by large or small. 

The simplest measurement to use, and the most common in our school geographies, is length. Length is most 

meaningful in comparing navigable rivers. The thousands 

of miles of navigation afforded by the Mississippi-OhioMissouri River system played a large and significant part 

in the development of the interior of our country. The 

great navigable length of the Missouri made it an important arterial trail to the West. It is interesting to consider 

the profound extent to which the settlement of the West 

might have been altered had the early Spanish settlers in 

Mexico been able to ascend the Colorado by boat. 

Rivers may also be compared in relation to the size of 

the basin drained. Drainage area is a measure of the 

region contributory to a river, but is not so much a 

characteristic of the river itself. 

It is the flow of water in the river that turns the 

wheels of industry, supplies water for cities and for innumerable industrial processes, and maintains navigable 

depths for shipping. Consequently, the flow of a river is 

perhaps the most significant index of its utility in a 

highly productive country. It tells us how much water 

the river can supply for development. Therefore, in this 

report, rivers are classified with respect to their flows. 

Their lengths and their drainage areas are listed for subsidiary classification. 

MEASUREMENT OF DISCHARGE 

Possibly the first effort to classify rivers on the basis 

of discharge was made in 1880 by H. B. Guppy ,I a 

British naturalist. Dr. Guppy, who had made some measurements of the Yangtse River, the Yellow River, and 

the Pei-ho in China, using floats and sounding lines, was 

curious to know how his measurements compared with 

measurements on other rivers of the world. He was able 

to collect information as to the relative magnitude of the 

flow of 17 rivers. In 1880, facts on riverflow were obtained only by specially investigative-minded individuals 

like Dr. Guppy and published data were very limitedand still are in many parts of the world. About this time 

the U.S. Geological Survey began its river measurement 

work in the West to obtain needed streamflow information so that settlers and other water users might know 

how much water was available for irrigation and other 

purposes. Because water users in other parts of the country also needed streamflow information, the U.S. Geological Survey expanded its gaging station network and 

now collects stage and discharge data at about 16,000 

sites, including those near the mouths of most of the 

large rivers of the United States. 

The stream-gaging stations are maintained in cooperation with Federal, State, county, municipal, and other 

organizations. Collection of stage and discharge data at 

these stations is the foundation necessary for all types of 

water-resources investigations and research. This basic 

1 Guppy, H. B., 1880, Nature: v. 22, p. 486-488. 
information is needed in studies in hydraulics and 

hydrology and in engineering studies related to design, 

construction, and operation of hydraulic structures. This 

information also is needed in making sound decisions 

concerning water-management and use, in determining 

the water rights of individuals and groups, in alleviating 

water shortages and pollution, in determining the magnitude and frequency of floods, and for many other 

purposes. 

Various techniques and equipment are used to obtain 

streamflow measurements. At St. Louis, Mo., measurements of flow of the Mississippi River are made from a 

car suspended from a monorail beneath the bridge deck 

(fig. 1 ). At other bridge sites, measurements are obtained 

Figure I.-Mississippi River at St. Louis, Mo. The flow of the 

Mississippi River at St. Louis is measured from a bridge. Depth 

and velocity are determined by use of current meter and 

sounding weight suspended from an electrically driven car, 

wh1ch travels along a monorail beneath the bridge deck. 

Waterway traffic is monitored with closed-circuit television 

camera. Photograph by Joseph C. Moore. 

2 

from instruments suspended from a crane mounted on a 

truck (fig. 2). On estuaries and large streams and 

Figure 2.-At some bridge sites, streamflow measurements are 

obtained by use of current meter and sounding weight suspended from a crane mounted on a truck. 

especially during floods, river discharge measurements 

are made from moving boats (fig. 3). 

A list of the gaging stations maintained by the U.S. 

Geological Survey near the mouths of the large rivers of 

the United States is given in table 1. The list includes the 

drainage area above each gaging station and the average 

discharge in cubic feet per second ( cfs) for two base 

periods-1931 - 60 and 1941-70. 

For practical reasons, it is seldom feasible to operate 

gaging stations in the immediate vicinity of the mouth of 

a large river. Therefore, in order to determine the flow at 

the mouth, it becomes necessary to add the inflow to 

the river below the most downstream gaging station. For 

most rivers this additional flow is minor in comparison 

with that measured at the gaging station. Flows at the 

mouth in cubic feet per second, and for the same base 

periods as in table 1, are listed in table 2 for the 28 

largest rivers in the country in order of volume of flow. 

The Mississippi River above the Missouri River is listed 

separately along with other major tributaries of the Mississippi, although it is a part of the Mississippi River 

listed at the head of table 2. No average figures of flow 

are shown for the Tennessee, Cumberland, Sacramento, 

and Colorado Rivers for 1941 - 70 because the 
Figure 3.-The moving-boat method is used for obtaining measurements rapidly on large streams and estuaries where no fixed 

measurement facilities exist. This method is also used during floods when facilities are inaccessible or inundated. 

unmeasured flow was so great in proportion to the total, 

or so uncertain, that no dependable estimate could be 

made for flow at the mouth. However, these rivers are 

listed in what is believed to be their proper rank in relation to others in the table. The information on discharge 

in tables 1 and 2 has been computed from basic data 

especially for this report. Data on lengths and drainage 

areas have been obtained from previously published 

sources. Lengths of rivers shown in table 2 are approximate. Changes in river channels may affect river lengths. 

Variations in techniques used to determine river lengths 

may also result in differences in river mileages. The locations of the rivers listed are shown in figure 4. The 

widths of the rivers represent their relative rates of flow. 

MISSISSIPPI RIVER SYSTEM 

The Mississippi, early named "Father of Waters," is 

the greatest river in the United States by all standards of 

3 

comparison-flow, drainage area, and length. Of the 

tributaries or components of the Mississippi River 

system, 11 are included among the ranking 28 rivers ir, 

the United States. The Mississippi, together with a parallel distributary, the Atchafalaya, discharges water that 

drains from 40 percent of the land area of the conterminous United States. 

The Atchafalaya River is shown as a continuation of 

the Red River and as one of the 28 large rivers of the 

United States. The Old River control structure located in 

Concordia Parish, La., prevents flow of Red River from 

entering the Mississippi River. The structure was completed in 1963. The Red River flows into the 

Atchafalaya River, which continues directly to the Gulf 

of Mexico. About 25 percent of the Mississippi River 

flow is diverted into the Red River by means of the 

control structure. Hence, the Atchafalaya River flow includes the diversion from the Mississippi River and the 

entire flow from the Red River basin. 
p;----__ ?9" ______________ _____ f\ 

"--._ 

, ____ ; -- ·\ 

EXPLANATION ·,, 

20,000 cubic feet pe~ second 

50,000 cubic feet per second 

1 00;000 cubic feet per second 

250,000 cubic feet per second 

500,000 cubic feet per second 

Rivers shown are those whose average flow at the 

mouth is 17,000 cubic feet per second or more. 

Average flow of Yukon River, Alaska, is 240,000 

cubic feet per second 

........._ ~-........~ ......--

100 0 100 200 300 MILES 

';~~~ ,~ 1~0 ~~ 3~~ ~METERS 

Figure Large rivers in the United States. 

BASE PERIODS 

Rivers vary in flow from year to year. In order to 

standardize results and to minimize the effects of these 

variations on the comparisons, the flows of all rivers 

have been based on the averages during the 30-year 

periods, 1931 - 60 and 1941 - 70. The rank of the rivers 

listed in table 2 may depend partly on the period of 

record on which the flows are based. For example, in a 

previous edition of this circular the flow of the 

Columbia River during the period 1921 - 45 is shown as 

being less than that of the Ohio River, whereas in this 

edition the flow of the Columbia River during the period 

1941- 70 is shown as the greater. Other reversals, where 

order of rank is based on small differences in flow , might 

also occur if the flows were based on a period other than 

1931 - 60 or 1941 - 70. 

The flows of many western rivers, such as the 

Columbia, Snake, Missouri, and Colorado, are reduced or 

depleted by diversions for irrigation. These diversions 

have not been considered in preparing table 2, except on 

the Colorado River, where no entry for the flow is given, 

but the relative position was based on estimates of the 

virgin flow (that is, by adding the depletions for irrigation to the measured flow). In general these diversions 

4 

would not greatly affect the relative position of the 

rivers listed. 

NAMES OF RIVERS 

Names of streams have little hydrologic significance, 

even though they may be of great historic and geographic interest. The rivers listed in table 2 bear the 

name of the stream at the mouth, because this is the 

point of greatest flow. The river lengths given in the 

table and shown in figure 4 represent not only the length 

of the stream bearing the given name, but the length of 

the river system, that is, distance from mouth to the 

most upstream source as measured along the watercourse. For the Mississippi River, the length listed is the 

distance along the stream from the Gulf of Mexico to 

the source of Red Rock River in the upper Missouri 

River basin in western Montana . 

The Mobile River, the eleventh ranking river in table 

2, is the name given to the meandering reach of river, 

about 45 miles long, which together with a parallel distributary , Tensaw River, carries the combined flow of 

the Alabama and Tombigbee Rivers to Mobile Bay. 

Among the 28 large rivers listed in table 2, only 11 are 

independent; that is, rivers that discharge directly into 
the ocean. The others, such as the Missouri and the 

Willamette, are tributary to larger streams included in 

the list and are therefore not independent. Some rivers, 

such as the Tennessee, are second-order tributaries; that 

is tributary to a tributary of a river that discharges into 

the ocean. Although it is common practice to follow 

accepted names in deciding which river is a tributary and 

which is the main river, it is largely a matter of historical 

accident which fork carries the name of the lower stream 

and which is separately named. 

SUMMARY 

The outflow of all streams from the conterminous 

United States into the oceans or across its boundaries is 

about 2,000,000 cubic feet per second. Of this total 

more than 75 percent is accounted for by the 11 independent streams that appear in table 2. The remaining 

25 percent is discharged through a host of comparatively 

minor coastal streams. 

We know only a little about rivers when we measure 

their lengths, drainage areas, and average flows. There is 

5 

much to be learned about their range from flood to 

drought, about their sources, about their chemical and 

biological quality and about their load of sediment as 

well as other physical, hydraulic, and geomorphic characteristics. The topography, geology, climate, and vegetation growing in various parts of these river basins as 

well as human activities, greatly affect streamflows and 

the character of our rivers. All these things must be 

known if we are to make the most effective use of our 

rivers, large and small. Maps of all kinds, especially topographic maps which show elevations of all streams, 

mountains, and plains, are a valuable aid in studying our 

rivers. 

ADDITIONAL INFORMATION 

Information on these subjects is contained in the 

water-supply papers, hydrologic atlases, topographic 

maps, and other publications of the Geological Survey, 

available in major libraries. A list is available on request 

to the Director, U.S. Geological Survey, National Center, 

Reston, Va., 22092. 

TABLES 1 and 2 
Table i.-Average discharge at downstream gaging stations on large rivers of the United States, 1931-60, and 1941-70 

River 

Alabama .............. . 

Allegheny ............. . 

Apalachicola ........... . 

Arkansas .............. . 

Atchafalaya 1 .......... . 

Colorado ............. . 

Columbia ............. . 

Cumberland ........... . 

Delaware ............. . 

Hudson ............... . 

Illinois ............... . 

Mississippi ............ . 

Mississippi ............ . 

Missouri .............. . 

Ohio ................. . 

Pend Oreille ........... . 

Red ................. . 

Sacramento ........... . 

St. Lawrence .......... . 

Snake ................ . 

Susquehanna .......... . 

Tennessee ............. . 

Tombigbee ............ . 

,Wabash ............... . 

White ................ . 

Willamette ............ . 

Yukon ............... . 

Gaging-station 

location 

At Claiborne, Ala ....................... . 

At Natrona, Pa ......................... . 

At Chattahoochee, Fla ................... . 

At Little Rock, Ark ..................... . 

At Krotz Springs, La .................... . 

Below Hoover Dam, Ariz.-Nev3 ........... . 

At The Dalles, Oreg ..................... . 

Near Grand Rivers, Ky ................... . 

At Trenton, N.J6 ......•...•••.•.•..•..•• 

At Green Island, N.Y .................... . 

At Merdosia, Ill ........................ . 

At Alton, Ill ........................... . 

At Vicksburg, Miss ...................... . 

At Hermann, Mo ....................... . 

At Metropolis, Ill ....................... . 

At international boundary ................ . 

At Alexandria, La ....................... . 

At Verona, Calif9 ....................... . 

At Cornwall, Ontario-near Massena, N.Y10 .. . 

Near Clarkston, Wash .................... . 

At Marietta, Pa ......................... . 

Near Paducah, Ky ....................... . 

At Jackson Lock and Dam near Coffeeville, Ala. 

At Mount Carmel, Ill .................... . 

At Clarendon, Ark ...................... . 

At Salem, Oreg ......................... . 

At Ruby, Alaska ........................ . 

1 Continuation of Red River. 

Drainage 

area 

(square miles) 

22,000 

11,410 

17,200 

158,000 

93,320 

167,800 

237,000 

17,598 

9,397 

8,090 

25,300 

171,500 

1,144,500 

528,200 

203,000 

25,200 

67,412 

299,000 

103,200 

25,990 

40,200 

18,500 

28,600 

25,497 

7,280 

259,000 

2 Includes diversion from Mississippi River through Old River or Old River diversion channel. 

Average Average 

discharge discharge 

(1931-60) (1941-70) 

(cubic feet (cubic feet 

per second) per second) 

31,140 31,510 

19,200 18,810 

20,700 21,700 

41,300 42,130 2 160,800 2 180,800 

4 14,580 14,530 

183,000 189,000 

26,900 5 28,030 

16,100 7 14,500 

. .......... 8 12,520 

20,500 20,670 

91,300 98,300 

554,000 565,300 

69,200 76,200 

257,000 257,200 

26,900 28,420 

32,470 32,100 

25,700 27,200 11 233,000 11 239,000 

48,600 48,960 

36,100 35,060 

63,400 5 64,050 

25,200 25,130 

26,400 26,600 

29,490 29,360 

23,870 24,780 

........... 12 170,000 

3 Very little tributary flow downstream. Downstream station located at Yuma, Ariz., drainage area 242,900 square miles. The 

greater part of the natural flow is diverted for irrigation and other uses in the basin above Yuma. Average flow at Yuma, 1963-70, is 

less than 1,000 cubic feet per second. 4 For the period 1934-60. 5 Interbasin diversion beginning June 1966 between Lake Barkley on Cumberland River and Lake Kentucky on Tennessee River 

through Barkley-Kentucky Canal. 6 Five tributaries below Trenton have been added. 7 Unadjusted for diversion by New York City reservoirs since 1954. 8 October 1946 to September 1970 (24 years). 9 American River and Yolo bypass have been added. 1 °Formerly at Ogdensburg, N.Y. 1 1 Furnished by the U.S. Army Corps of Engineers through International St. Lawrence River Board of Control. 12 Average is for 1957 -70; station operated only since 1956. 

Metric equivalents of measures used: 

1 square mile = 2.590 square kilometers 

1 cubic foot per second = 0.0283 cubic meter per second 

1 mile = 1.6093 kilometers 

8 
Table 2.-Large rivers in the United States in order of average discharge at mouth, 1931-60, 1941-70. Order based on average 

discharge for 1941-70 

Rank River 

Mississippi ...... . 

2 Columbia ....... . 

3 Ohio ........... . 

4 St. Lawrence .... . 

5 Yukon ......... . 

6 A tchafalaya 7 ••••• 

7 Mississippi above 

Missouri River. 

8 Missouri ........ . 

9 Tennessee ....... . 

10 Red ........... . 

11 Mobile ......... . 

12 Snake .......... . 

13 Arkansas ........ . 

14 Susquehanna .... . 

15 Willamette ...... . 

16 Alabama ........ . 

17 White .......... . 

18 Wabash ......... . 

19 Pend Oreille ..... . 

20 Tombigbee ...... . 

21 Cumberland 

22 Sacramento 

23 Apalachicola ..... . 

24 Illinois ......... . 

25 Colorado ....... . 

26 Hudson ......... . 

27 Allegheny ....... . 

28 Delaware ....... . 

Drainage 

area 

(square 

miles) 

1 1,24 7,266 

258,000 

203,900 

5 302,000 

327,600 

95,105 

171,600 

529,400 

40,910 

93,244 

9 43,800 

109,000 

160,600 

27,570 

11,200 

22,600 

28,000 

33,150 

25,820 

20,100 

18,080 

27,100 

19,600 

27,900 

10 242,900 

13,370 

11,700 

11 11,440 

1 At Baptiste Collette Bayou,La. 

Average 

discharge 

(1931-60) 

(cubic feet 

Average 

discharge 

(1941-70) 

(cubic feet 

per second) per second) 

2 650,000 

253,000 

258,000 

5 238,000 

161,000 

91,400 

69,300 

64,000 

64,000 

61,100 

49,500 

41,900 

38,200 

34,170 

32,000 

32,300 

30,000 

27,600 

27,400 

26,900 

24,200 

22,600 

21,300 

19,800 

12 19,200 

2 •

3 640,000 

262,000 

258,000 

5 243,000 

6 240,000 

183,000 

98,400 

76,300 

(8) 

62,300 

61,400 

50,000 

45,100 

37,190 

35,660 

32,400 

32,100 

30,400 

29,900 

27,300 

(8) 

24,700 

22,800 

19,500 

19,290 

17,200 

Length 

(miles) 

Most distant 

source 

4 3, 710 Source of Red Rock 

River, Mont. 

1,243 Columbia Lake, B.C 

1,306 Source of Allegheny 

River, Potter Co., Pa. 

1,770 Coast Mountains, B.C 

135 Eastern edge of New 

Mexico. 

1,170 Lake Itasca, Minn ..... . 

2,533 Source of Red Rock 

900 

1,270 

780 

1,038 

1,450 

444 

270 

735 

720 

529 

490 

525 

720 

377 

524 

420 

10 1,360 

306 

River, Mont. 

Southwest Virginia, North 

Fork Holston River. 

Eastern edge of New 

Mexico. 

Northwest Georgia ..... 

Ocean Plateau, Teton 

Co., Wyo. 

Lake Co., Colo ....... . 

Otsego Lake, Otsego 

Co., N.Y. 

Tumblebug Creek, 

Douglas Co., Oreg. 

Northwest Georgia .... . 

Madison Co., Ark ..... . 

Darke Co., Ohio ...... . 

Near Butte, Mont ..... . 

Northeast Mississippi ... . 

Poor Fork, Letcher 

Co., Ky. 

Siskiyou Co., Calif ..... 

Source of Chattahoochee 

River, Towns Co., Ga. 

Source of Kankakee River, 

St. Joseph Co., Ind. 

Rocky Mountain National 

Park, Colo. 

Essex Co., N.Y ....... . 

325 Source of Allegheny 

River, Potter Co., Pa. 1 1 390 Source of West Branch, 

Schoharie Co., N.Y. 

2 About 25 percent of the flow of the Mississippi River system occurs in the Atchafalaya River. 

Mouth 

Gulf of Mexico. 

Pacific Ocean. 

Mississippi River. 

Bering Sea. 

Gulf of Mexico. 

Confluence with 

Missouri River. 

Mississippi River. 

Ohio River. 

Atchafalaya River. 

Mobile Bay. 

Columbia River. 

Mississippi River. 

Chesapeake Bay. 

Columbia River. 

Mobile River. 

Mississippi River. 

Ohio River. 

Columbia River. 

Mobile River. 

Ohio River. 

Suisun Bay. 

Gulf of Mexico. 

Mississippi River. 

Gulf of California. 

Upper New York 

Bay. 

Ohio River. 

Delaware Bay. 

3 Combined flow of Mississippi and Atchafalaya Rivers is 640,000 cubic feet per second. Flow of Mississippi River channel at 

mouth is 453,000 cubic feet per second. 4 Measured from the mouth of the Mississippi River and along its watercourse and that of the Missouri River to the source of Red 

Rock River in Montana. The length from mouth of Mississippi River to its source in Minnesota is 2,340 miles. 5 At international boundary, lat. 45°. Includes flow of St. Regis River. 6 Average is for 1957-70 period; station operated only since 1956. 7 Continuation of Red River. 8 1nterbasin diversion beginning June 1966 between Lake Barkley on Cumberland River and Lake Kentucky on Tennessee River 

through Barkley-Kentucky Canal. 9 At Bankhead Tunnel. 1 0 At Arizona-Sonora boundary; natural flow not accurately known because of large depletions for irrigation. 11 At Liston Point on Delaware Bay. 1 2 Does not include flow of Chesapeake and Delaware canal. 

9 
The following rivers, mainly in the Southwest, have large drainage areas but relatively low average flows. They are 

listed according to drainage area, and are believed to discharge less than 10,000 cubic feet per second. Colorado 

River above its junction with Green RiveT in Utah is believed to be the largest in the group on a flow basis. 

Rio Grande 

Platte River 

Kansas River ............................. . 

Gila River ............................... . 

Brazos River ............................. . 

Green River (Utah-Wyo.) ................... . 

Square miles 

171,585 

90,000 

61,300 

58,100 

44,500 

44,400 

10 

Colorado River (Texas) ..................... . 

Red River of the North (at U.S.-Canadian 

boundary) ............................. . 

Pecos River .........•..................... 

Canadian River ........................... . 

Colorado River (above Green River) ........... . 

Square miles 

41,500 

40,200 

38,300 

29,700 

26,500 

*u.s. GOVERNMENT PRINTING OFFICE: 1975 0-585-471/6 9