Flathead County is in the U.S. state of Montana. At the 2020 census, its population was 104,357, making it the state's fourth most populous county. Its county seat is Kalispell. Its numerical designation is 7. Its northern border is on the state's north border, making it contiguous with the Canada–US border, facing British Columbia.

The Kootenai National Forest is a national forest located in the far northwestern section of Montana and the northeasternmost lands in the Idaho panhandle in the United States, along the Canada–US border. Of the 2.2 million acres (8,900 km2) administered by the forest, less than 3 percent is located in the state of Idaho. Forest headquarters are located in Libby, Montana. There are local ranger district offices in Eureka, Fortine, Libby, Trout Creek, and Troy, Montana. About 53 percent of the 94,272-acre (381.51 km2) Cabinet Mountains Wilderness is located within the forest, with the balance lying in neighboring Kaniksu National Forest.