what county is flagstaff in
Flagstaff Community Profile. Flagstaff, Arizona is located at the intersection of I-17 and I-40, and is the largest city in Northern Arizona. The City is also the regional center and county seat for Coconino County, the second largest county in the 48 contiguous states (by area). The City of Flagstaff is comprised of just over 64 square miles nestled at the base of the San Francisco Peaks.