U.S. International Borders: Brief Facts

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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.

Canadian and Mexican Borders.......................................................................................................1
U.S. Coastline..................................................................................................................................2
Great Lakes Shorelines....................................................................................................................3
CRS Reports on Border Security Issues..........................................................................................4
Selected Print Sources.....................................................................................................................4
Selected Internet Sources................................................................................................................5
Table 1. Length of U.S.-Canada Land and Water Boundary by State.............................................1
Table 2. Length of U.S.-Mexico Land and Water Boundary, by State............................................1
Table 3. Length of the U.S. Coastline..............................................................................................2
Table 4. Great Lakes Shorelines and Connecting Rivers................................................................3
Author Contact Information............................................................................................................5

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 descendin}^g^order^{in miles)}
^{State Boundary}^Length
^{Alaska 1,53}⁸
^{Michigan 721}
^{Maine 611}
^{Minnesota 547}
^{Montana 545}
^{New York}⁴⁴⁵
^{Washington 427}
^{North Dakota}³¹⁰
^{Ohio 146}
^{Vermont 90}
^{New Ham}^pshire⁵⁸
^{Idaho 45}
^{Pennsylvania 42}
^{Total 5,52}⁵
^Source:^Int^{ernational Boundary}^{Commission. http://www.internationalboundarycommission.org/ibcpg2.htm}
Table 2. Length of U.S.-Mexico Land and Water Boundary, by State
^{(in descendin}^g^order^{in miles)}
^{Border Length}
^State^{(including al}^{ong the Rio}
^Grande)
^Texas^1,24^1.0
^{Arizona (including 19.1 miles along the Colorado}^372.⁵
^River)
^{New Me}^xico^179.⁵
^{California 140.}⁴
^Total^1,93^3.⁴
^Source:^{U.S. Geolog}^{ical Survey and CRS phone con}^{sultation with}^{USGS library.}
^Note:^{The border area in th}^{e U}^{nited States consists of four}^state^s.

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 ^th
the nearly 900-mile section of the U.S.-Canadian border along the 49 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 Stat}^es^{General Coastline}
^Maine²²⁸
^{New Ham}^pshire¹³
^Massach^{usetts 192}
^{Rhode Island}⁴⁰
^Connecticut⁰^a
^{New York}¹²⁷
^{New Jers}^ey¹³⁰
^Delaware²⁸
^Maryland³¹
^Virginia¹¹²
^{North Carolina}³⁰¹
^{South Carolina}¹⁸⁷
^Georgia¹⁰⁰
^Florida^1,35⁰
^Alabama⁵³
^Mississippi⁴⁴

^{United Stat}^es^{General Coastline}
^Louisiana³⁹⁷
^Texas³⁶⁷
^California⁸⁴⁰
^Oregon²⁹⁶
^Washington¹⁵⁷
^Alaska^6,64⁰
^Hawaii⁷⁵⁰
^Total^12,3⁸³
^Source:^{U.S. Department of Co}^{mmerce, National Oceanic a}^{nd A}^{tmospheric Administration,}^{The Coastline of the}
^{United States}^{, 197}^5.
^a.^{Although Conne}^{cticut ha}^{s ap}^pro^{ximately 11}^{0 miles of coastline, none of it borders on inte}^rnationa^{l waters.}
^{Source for this infor}^{mation: Office of Long Island Sound Program}^{s, Connecticut Program}^{s Office. C}^ontacted
^1/23/²⁰^07.

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 Supe}^rior^1,25⁰
^{St. Marys River}¹²⁰
^{Lake Michigan}^1,64⁰
^{Lake Hu}^ron⁸⁴⁰
^{St. Cla}^{ir River}³⁰
^{Lake St. Clair}¹⁴⁰
^{Detroit River}⁷⁰
^{Lake Erie}⁴⁷⁰
^{Niagara River}⁷⁰
^{Lake Onta}^rio³³⁰
^Total^4,96⁰

^{Body of}^Water^{U.S. Shoreline}
^{St. Lawrence River (above I}^roqu^{ois Dam)}²²⁰
^{St. Lawrence River (above Power}^Dam)³²⁰
^Source:^{U.S. Department of Co}^{mmerce, National Oceanic a}^{nd A}^{tmospheric Administration,}^{The Coastline of the}
^{United States}^{, 197}^5.

CRS Report RS22026, Border Security: The San Diego Fence, by Blas Nuñez-Neto and Michael
John Garcia.
CRS Report RL33659, Border Security: Barriers Along the U.S. International Border, by Blas
Nuñez-Neto and Yule Kim.CRS Report RL33353, Civilian Patrols Along the Border: Legal
and Policy Issues, by Stephen R. Vina and Blas Nuñez-Neto.
CRS Report RS22443, Border Security and Military Support: Legal Authorizations and
Restrictions, by Stephen R. Vina.
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 Ruth
Ellen Wasem et al., Border Security: Inspections Practices, Policies, and Issues, coordinated
by Ruth Ellen Wasem.

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.

International Boundary and Water Commission (IBWC) United States and Mexico
http://www.ibwc.stat e.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.int ernati onalboundarycommission.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.
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^In^f^o^r^m^a^tion^R^e^s^earch^Specialⁱ^s^t
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