Idaho vs. South Dakota: Which State Borders Canada?

If you're looking at a map of the northern United States, you might wonder which states actually touch Canada. Between Idaho and South Dakota, the answer is clear: Idaho shares an international border with Canada, while South Dakota does not.

Idaho's northern boundary runs along the 49th parallel for approximately 45 miles (72 km), bordering the Canadian province of British Columbia. This relatively short border segment sits in the state's panhandle region, north of Coeur d'Alene. The crossing at Porthill connects to Rykerts, BC.

South Dakota, by contrast, lies entirely in the north-central U.S., separated from Canada by the entire width of North Dakota. The distance from South Dakota's northern border to the Canadian border is roughly 350 miles (560 km)—a full day's drive.

This geographic distinction matters for trade, tourism, and cross-border commuting. Idaho's northern communities like Bonners Ferry and Sandpoint have deep economic and cultural ties to British Columbia, while South Dakota's international connections run through North Dakota's ports of entry.

Other states bordering Canada include Washington, Montana, North Dakota, Minnesota, Michigan, New York, Vermont, New Hampshire, Maine, and Alaska.