U.S. International Borders: Brief Facts

This report, originally authored by CRS Information Specialist Barbara Torreon, provides information on the international boundaries that the United States shares with Canada and Mexico. Included are data on land and water boundaries for the northern Canadian border and the southern Mexican border, as well as the international boundaries for the U.S. states that border these countries. Coastline figures for the continental United States, Alaska, Hawaii, the Great Lakes, and extraterritorial areas are also included. This report does not cover border security issues; however, a listing of relevant CRS reports is at the end of this report. This report will be updated as needed.

U.S. International Borders: Brief Facts

February 1, 2007 (RS21729)

Summary

This report, originally authored by CRS Information Specialist Barbara Torreon, provides information on the international boundaries that the United States shares with Canada and Mexico. Included are data on land and water boundaries for the northern Canadian border and the southern Mexican border, as well as the international boundaries for the U.S. states that border these countries. Coastline figures for the continental United States, Alaska, Hawaii, the Great Lakes, and extraterritorial areas are also included. This report does not cover border security issues; however, a listing of relevant CRS reports is at the end of this report. This report will be updated as needed.


U.S. International Borders: Brief Facts

Canadian and Mexican Borders

According to the U.S. Geological Survey (USGS), the length of the International Boundary line of the U.S.-Canadian border, excluding Alaska, is approximately 3,987 miles, while the length of the U.S.-Mexican border is estimated at 1,933 miles. The length of the Alaska-Canada border alone is 1,538 miles. The tables below list the 13 U.S. states that share international boundaries with Canada and the four states that share an international border with Mexico, with information from the International Boundary Commission and the U.S. Geological Survey.

Table 1. Length of U.S.-Canada Land and Water Boundary by State

(in descending order in miles)

State

Boundary Length

Alaska

1,538

Michigan

721

Maine

611

Minnesota

547

Montana

545

New York

445

Washington

427

North Dakota

310

Ohio

146

Vermont

90

New Hampshire

58

Idaho

45

Pennsylvania

42

Total

5,525

Source: International Boundary Commission. http://www.internationalboundarycommission.org/ibcpg2.htm

Table 2. Length of U.S.-Mexico Land and Water Boundary, by State

(in descending order in miles)

State

Border Length
(including along the Rio Grande)

Texas

1,241.0

Arizona (including 19.1 miles along the Colorado River)

372.5

New Mexico

179.5

California

140.4

Total

1,933.4

Source: U.S. Geological Survey and CRS phone consultation with USGS library.

Note: The border area in the United States consists of four states.

U.S. Coastline

The National Oceanic and Atmospheric Administration (NOAA) has surveyed the coastline of the continental United States, Alaska, and Hawaii several times. The current figures for the coastline are the results of the measurements done originally in 1915 and updated several times thereafter. These figures reflect the general outline of the seacoast. The figures for Alaska reflect a 1961 remeasurement.

It is important to note that boundary and coastline distances can differ significantly based on the scale used on the maps or charts. The Canadian and Mexican international borders are less problematic than the coastline measures because there are long stretches that are straight, such as the nearly 900-mile section of the U.S.-Canadian border along the 49th parallel.

Coastline measurements are more difficult because of the effects of tides and the necessarily arbitrary decisions that must be made about measuring bays, coves, islands, and inlets leading to streams and rivers. The "general coastline" data in this report are based on large scale nautical charts, resulting in a coastline measure for the 50 states totaling12,383 miles. Another measure using smaller scale nautical charts more than doubles this measurement to 29,093 miles, while the figures used by the NOAA in administering the Coastal Zone Management program (16 U.S.C. §1451) come to 88,612 miles (not including the Great Lakes).

Table 3 provides figures for the areas of the U.S. coastline bordering international waters. It measures the coastline of the contiguous states from northeast to northwest.

Table 3. Length of the U.S. Coastline

(in miles)

United States

General Coastline

Maine

228

New Hampshire

13

Massachusetts

192

Rhode Island

40

Connecticut

0a

New York

127

New Jersey

130

Delaware

28

Maryland

31

Virginia

112

North Carolina

301

South Carolina

187

Georgia

100

Florida

1,350

Alabama

53

Mississippi

44

Louisiana

397

Texas

367

California

840

Oregon

296

Washington

157

Alaska

6,640

Hawaii

750

Total

12,383

Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, The Coastline of the United States, 1975.

a. Although Connecticut has approximately 110 miles of coastline, none of it borders on international waters. Source for this information: Office of Long Island Sound Programs, Connecticut Programs Office. Contacted 1/23/2007.

Great Lakes Shorelines

Similar to problems mentioned above regarding measuring coastlines, variations in shoreline figures appear due to natural occurrences, including bays and inlets, and in differing methods of measurement.

These shoreline lengths were measured in 1970 by the International Coordinating Committee on the Great Lakes Basic Hydraulic and Hydrologic Data.

Table 4. Great Lakes Shorelines and Connecting Rivers

(in miles)

Body of Water

U.S. Shoreline

Lake Superior

1,250

St. Marys River

120

Lake Michigan

1,640

Lake Huron

840

St. Clair River

30

Lake St. Clair

140

Detroit River

70

Lake Erie

470

Niagara River

70

Lake Ontario

330

Total

4,960

St. Lawrence River (above Iroquois Dam)

220

St. Lawrence River (above Power Dam)

320

Source: U.S. Department of Commerce, National Oceanic and Atmospheric Administration, The Coastline of the United States, 1975.

CRS Reports on Border Security Issues

CRS Report RS22026, Border Security: The San Diego Fence, by [author name scrubbed] and [author name scrubbed].

CRS Report RL33659, Border Security: Barriers Along the U.S. International Border, by [author name scrubbed] and Yule Kim.CRS Report RL33353, Civilian Patrols Along the Border: Legal and Policy Issues, by [author name scrubbed] and [author name scrubbed].

CRS Report RS22443, Border Security and Military Support: Legal Authorizations and Restrictions, by [author name scrubbed].

CRS Report RL33106, Border Security and the Southwest Border: Background, Legislation, and Issues, by Lisa M. Seghetti et al..

CRS Report RL31826, Protecting the U.S. Perimeter: "Border Searches" Under the Fourth Amendment, by Yule Kim.

CRS Report RL32399, Border Security: Inspections Practices, Policies, and Issues, by [author name scrubbed] et al., Border Security: Inspections Practices, Policies, and Issues, coordinated by [author name scrubbed].

Selected Print Sources

Shalowitz, Aaron L. Shore and Sea Boundaries, vol. 2. Washington: U.S. Dept. of Commerce, Coast and Geodetic Survey, 1964. Coast and Geodetic Survey Publication 10-1.

U.S. Census Bureau. Statistical Abstract of the United States 2007. Washington: GPO, 2006.

U.S. Department of Commerce, National Oceanic and Atmospheric Administration. The Coastline of the United States, 1975.

Van Zandt, Franklin K. Boundaries of the United States and the Several States. Washington: GPO, 1976. Geological Survey Professional Paper 909.

The World Almanac and Book of Facts 2007.

Selected Internet Sources

International Boundary and Water Commission (IBWC) United States and Mexico
http://www.ibwc.state.gov

This website has historical information on the two treaties—the Guadalupe Hidalgo Treaty of February 2,1848, and the Treaty of December 30, 1853—between the United States and Mexico that set the international boundary between the two countries. Also included is information on additional conventions and treaties between the two nations on maintaining the Rio Grande and Colorado Rivers, as well as current IBWC reports and solutions for boundary and water problems.

International Boundary Commission between Canada and the United States
http://www.internationalboundarycommission.org

This website contains information on the Treaty of 1908 between the United States and Canada that completed the mapping of the international boundary from the Atlantic Ocean to the Pacific Ocean. Information on U.S.-Canadian border history and boundary markings along open vistas is also included.