Post Falls is a city in Kootenai County, Idaho, United States. It is the gateway city to North Idaho on I-90 just west of Coeur d'Alene and east of Spokane, Washington. The population was 38,485 at the 2020 census, making it Idaho's ninth-largest city and the second largest city in North Idaho behind Coeur d’Alene.

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.