Which U.S. States Border Another Country?

Four U.S. states share an international land border—all with Canada:

1. Alaska – 1,538 miles (2,475 km) border with Yukon and British Columbia; the longest state-international boundary.
2. Washington – 427 miles (687 km) border with British Columbia; includes land and maritime boundaries (Strait of Juan de Fuca, Puget Sound).
3. Maine – 611 miles (983 km) border with Quebec and New Brunswick; heavily forested, with major crossings at Calais, Houlton, and Jackman.
4. Michigan – 721 miles (1,160 km) maritime border with Ontario across Lake Superior, Lake Huron, Lake Erie, and the Detroit/St. Clair River system. No land border, but significant water boundary with international ports (Detroit-Windsor, Port Huron-Sarnia).

Note: States bordering Mexico (California, Arizona, New Mexico, Texas) share a land border with another country. The question specifies "border another country" without distinguishing land vs. water. If including maritime borders, Michigan qualifies; if strictly land borders, the four Mexican-border states replace Michigan. Clarify the definition for precision.