Kootenai County is located in the U.S. state of Idaho. As of the 2020 census, its population was 171,362, making it the third-most populous county in Idaho and by far the largest in North Idaho, the county accounting for 45.4% of the region's total population. The county seat and largest city is Coeur d'Alene. The county was established in 1864 and named after the Kootenai tribe.

Coeur d'Alene is a city and the county seat of Kootenai County, Idaho, United States. It is the most populous city in North Idaho and the principal city of the Coeur d'Alene Metropolitan Statistical Area. The population was 54,628 at the 2020 census. Coeur d'Alene is a satellite city of Spokane, which is located about thirty miles (50 km) to the west in the state of Washington. The two cities are the key components of the Spokane–Coeur d'Alene Combined Statistical Area, of which Coeur d'Alene is the third-largest city. The city is situated on the north shore of the 25-mile (40 km) long Lake Coeur d'Alene and to the west of the Coeur d'Alene Mountains. Locally, Coeur d'Alene is known as the "Lake City," or simply called by its initials, "CDA."