United States share international border with Canada and Mexico. Canada, the world’s second largest country, and the United States (fourth largest) share the longest international border between two countries in the world.
According to the U.S. Geological Survey (USGS), the length of the International Boundary line of the US-Canadian border, excluding Alaska, is approximately 3,987 miles, while the length of the US-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.
Length of U.S.-Canada Land and Water Boundary by State (in descending order in miles)
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
Length of U.S.-Mexico Land and Water Boundary, by State (including along the Rio Grande; in descending order in miles)
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
For more information on the international boundaries that the United States shares with Canada and Mexico, see CRS Report for Congress' U.S. International Borders: Brief Facts.
See 10 Longest Land Borders In The World from 10MostToday.com.