Homes for Sale in Boundary County: Boundary County is a county located in the U.S. state of Idaho. As of the 2010 census, the population was 10,972. The county seat and largest city is Bonners Ferry.
Boundary County was created by the Idaho Legislature on January 23, 1915. It is so named because it borders Canada, and is therefore the only county in Idaho with an international border. It is also only one of two counties in the United States that borders two states and a foreign country, the other being Coös County, New Hampshire.