The United States shares international land borders with two nations: * The Canada–United States border to the north of the Contiguous United States and to the east of Alaska * The Mexico–United States border to the south. * The Russia–United States maritime boundary was defined by a disputed agreement covering the Bering Sea, Bering Strait, and Arctic Ocean. The International Date Line essentially acts as the de facto border between the two nations; the USA ratified the USSR–USA Maritime Boundary Agreement, but the USSR failed to ratify it before dissolving, and it was subsequently never ratified by Russia. During the winter, travel between Russia's uninhabited Big Diomede Island and Alaska's Little Diomede Island with a population of 110 is theoretically possible, although not legal, on some occasions when ice flowing through the Bering Strait clogs between the two islands. West of Puerto Rico, the Mona Passage serves as maritime boundary with the Dominican Republic, and the US shares a border with the United Kingdom east of the US Virgin Islands. The Third Border Initiative is an area of foreign policy concerning the Caribbean Sea border between the United States and the Caribbean region. Insular areas in the Pacific, and the U.S. Virgin Islands are in a separate customs territory from the 50 States, the District of Columbia, and Puerto Rico (see Foreign trade of the United States). In the continental United States, the country shares maritime borders with Cuba and the Bahamas, while sharing maritime borders with the United Kingdom in the Virgin Islands, the Dominican Republic and Venezuela in Puerto Rico, and Samoa in American Samoa.

Border disputes

The US also has disputed land borders with seven nations: * ** Machias Seal Island and North Rock (New Brunswick and Maine) - Occupied by Canada and patrolled by the Canadian Coast Guard, claimed by the US. * ** Guantanamo Bay Naval Base - Since the Cuban Revolution of 1959, the Cuban communist government has consistently protested against the U.S. presence on Cuban soil and called it "illegal" under international law. The US acquired the bay from the Spanish-American War as a lease from Cuba. * ** Navassa Island - The US claimed the Navassa island via the Guano Islands Act of 1856. Haiti claimed sovereignty over the island in 1801, but was occupied by the US through gunboat diplomacy. * , , ** Bajo Nuevo Bank - Administered by Colombia, claimed by the US as an unorganized, unincorporated territory. * , , ** Serranilla Bank - Administered by Colombia, claimed by the US as an unorganized, unincorporated territory. Additionally, the US has maritime border disputes with Canada: * Strait of Juan de Fuca * Beaufort Sea - Yukon–Alaska dispute * Dixon Entrance - Dispute stems from the ambiguity of the Hay–Herbert Treaty in 1903 between the United States and the United Kingdom signed to settle the Alaska boundary dispute, an agreement opposed by Canadian leaders.


U.S. Customs and Border Protection is responsible for policing the borders and inspecting people and goods being imported. The United States Coast Guard actively patrols the nation's extensive maritime borders. The United States Armed Forces and state and local police may also become involved in border enforcement in certain circumstances.

Total list

See also

* Border irregularities of the United States


External links

Border Security
at CBP
Secure and Manage Borders
at DHS
Border Security
at the WhiteHouse.gov
The Constitution in the 100-Mile Border Zone
at ACLU {{North America topic |Borders of Category:Geography of the United States