There are two international borders between Canada and the United States: Canada's border with the northern tier of the contiguous United States to its south (6,416 km (3,987 mi) long), and with the U.S. state of Alaska to its northwest (2,475 km (1,538 mi) long). The section between Canada and the contiguous United States is the second longest continuous international border in the world after the Kazakhstan–Russia border, and the two sections together form the longest border by total length.
The boundary (including boundaries in the Pacific coasts, Great Lakes, and Atlantic coasts) is 8,891 km (5,525 mi) long. The bi-national International Boundary Commission deals with matters relating to marking and maintaining the boundary, and the International Joint Commission deals with issues concerning boundary waters. The agencies responsible for facilitating legal passage through the international boundary are the Canada Border Services Agency (CBSA) and U.S. Customs and Border Protection (CBP).