The proportion chosen for a particular

map is its scale. Selecting the appropriate

scale depends on the size of the sheet of

paper and the accurate placement of

features. Ground area, rivers, lakes,

roads, distances between features, and so

on must be shown proportionately smaller

than they really are. 

Large Is Small

Simply defined, scale is the relationship

between distance on the map and distance

on the ground. A map scale usually is

given as a fraction or a ratio—1/10,000 or

1:10,000.

These "representative fraction" scales

mean that 1 unit of measurement on the

map—1 inch or 1 centimeter—represents

10,000 of the same units on the ground.

If the scale were 1:63,360, for instance,

then 1 inch on the map would represent

63,360 inches, or 1 mile, on the ground

(63,360 inches divided by 12 inches

equals 5,280 feet, or 1 mile). The first

number (map distance) is always 1. The

second number (ground distance) is

different for each scale; the larger the

second number is, the smaller the scale of

the map. "The larger the number, the

smaller the scale" sounds confusing, but

it is easy to understand. A map of an area

100 miles long by 100 miles wide drawn

at a scale of 1:63,360 would be more than

8 feet square. To make the map a more

convenient size, either the scale used or

the area covered must be reduced.

If the scale is reduced to 1:316,800, then 

1 inch on the map represents 5 miles on

the ground, and an area 100 miles square

can be mapped on a sheet less than 2 feet

square (100 miles at 5 miles to the inch

equals 20 inches, or 1.66 feet). On the

other hand, if the original 1:63,360 scale

is used but the mapped area is reduced to

20 miles square, the resulting map will

also be less than 2 feet square.

Such maps would be easier to handle.

But would they be more useful? In the

small-scale map (1:316,800), there is less

room; therefore, everything must be

drawn smaller, and some small streams,

roads, and landmarks must be left out

altogether. On the other hand, the larger

scale map (1:63,360) permits more detail

but covers much less ground.

Many areas have been mapped at

different scales. The most important 

consideration in choosing a map is its

intended use. A town engineer, for

instance, may need a very detailed map to

locate precise sewers, power and water

lines, and streets. A commonly used

scale for this purpose is 1:600 (1 inch on

the map represents 50 feet on the

ground). This scale is so large that many

features—such as buildings, roads, and

railroad tracks—can be drawn to scale

instead of being represented by symbols.

U.S. Geological Survey Scales 

The U.S. Geological Survey (USGS)

publishes maps at various scales. The

scale used for most U.S. topographic

mapping is 1:24,000. USGS maps at this

scale cover an area measuring 7.5

minutes of latitude and 7.5 minutes of

longitude and are commonly called 7.5-

minute quadrangle maps. Map coverage

for most of the United States has been

completed at this scale, except for Puerto

Rico, which is mapped at 1:20,000 and

1:30,000, and for a few States that have

been mapped at 1:25,000. Most of

Alaska has been mapped at 1:63,360,

with some populated areas also mapped

at 1:24,000 and 1:25,000.

Maps at 1:24,000 scale are fairly large

and provide detailed information about

the features of an area, including the

locations of important buildings and most

U.S. Department of the Interior

U.S. Geological Survey

Map Scales

USGS Fact Sheet 015-02

February 2002

1:20,000-scale map 1:63,360-scale map 1:500,000-scale map
campgrounds, ski lifts, and water mills.

Footbridges, drawbridges, fence lines,

and private roads are also shown at this

scale. Usually these features are omitted

from maps in the 1:50,000- to 1:100,000-

scale range; these maps cover more area

while retaining a reasonable level of

detail. Maps at these scales are most often

produced using the 30- by 60-minute

quadrangle formats.

Small-scale maps (1:250,000 and smaller)

show large areas on single map sheets, 

but details are limited to major features,

such as boundaries, parks, airports, major

roads, railroads, and streams.

Information

The table below shows information about

maps available from the USGS. For

information on other USGS products and

services, call 1-888-ASK-USGS, use the

Ask.USGS fax service, which is

available 24 hours a day at 703-648-4888,

or visit the general interest publications

Web site on mapping, geography, and

related topics at mac.usgs.gov/mac/isb/

pubs/pubslists/.

For additional information, visit the

ask.usgs.gov Web site or the USGS home

page at www.usgs.gov.

1:24,000-scale map 1:100,000-scale map 1:250,000-scale map

Puerto Rico 7.5 minute 1:20,000 1,667 feet 200 meters 7.5 by 7.5 minute 71

7.5 minute 1:24,000 2,000 feet (exact) 240 meters 7.5 by 7.5 minute 49 to 70

7.5 minute 1:25,000 2,083 feet 250 meters 7.5 by 7.5 minute 49 to 70 

7.5 by 15 minute 1:25,000 2,083 feet 250 meters 7.5 by 15 minute 98 to 140

USGS-DMA 15 minute 1:50,000 4,166 feet 500 meters 15 by 15 minute 197 to 282

15 minute* 1:62,500 1 mile 625 meters 15 by 15 minute 197 to 282

Alaska Maps 1:63,360 1 mile (exact) 633.6 meters 15 by 20 to 36 minute 207 to 281

County Maps 1:50,000 4,166 feet 500 meters County area Varies

County Maps 1:100,000 1.6 miles 1 kilometer County area Varies

30 by 60 minute 1:100,000 1.6 miles 1 kilometer 30 by 60 minute 1,568 to 2,240

30 minute* 1:125,000 2 miles 1.25 kilometers 30 by 30 minute 786 to 1,124

1 degree by 2 degrees or 3 degrees 1:250,000 4 miles 2.5 kilometers 1° by 2° or 3° 4,580 to 8,669

State Maps 1:500,000 8 miles 5 kilometers State area Varies

State Maps 1:1,000,000 16 miles 10 kilometers State area Varies

U.S. Sectional Maps 1:2,000,000 32 miles 20 kilometers State groups Varies

Antarctica Maps 1:250,000 4 miles 2.5 kilometers 1° by 3° to 15° 4,089 to 8,336

Antarctica Maps 1:500,000 8 miles 5 kilometers 2° by 7.5° 28,174 to 30,462

* Abandoned map series, but still available for ordering as black-and-white photographic reproductions.

USGS Maps

Standard Quadrangle

1 inch represents 1 centimeter quadrangle size area

Series Scale approximately represents (latitude by longitude) (square miles)