Idaho (Wikipedia) Idaho (/ˈaɪdəhoʊ/ EYE-də-hoh) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyoming to the east, Nevada and Utah to the south, and Washington and Oregon to the west. The state’s capital and largest city is Boise. With an area of 83,570 square miles (216,400 km2), Idaho is the 14th largest state by land area, but with a population of approximately 1.8 million, it ranks as the 13th least populous and the 7th least densely populated of the 50 U.S. states.