Flagstaff is the county seat of Coconino County, Arizona, in the southwestern United States. As of the 2020 United States census, the city's population was 76,831.

Coconino County is a county in the north-central part of the U.S. state of Arizona. Its population was 145,101 at the 2020 census. The county seat is Flagstaff. The county takes its name from Cohonino, a name applied to the Havasupai people. It is the second-largest county by area in the contiguous United States, behind San Bernardino County, California. It has 18,661 sq mi (48,300 km2), or 16.4% of Arizona's total area, and is larger than the nine smallest states in the U.S.