Coconino with Flagstaff as the county seat.
Coconino County: 18,661 square miles.
Coconino County and Flagstaff is the County Seat.
The second largest county in the lower 48 states is Coconino County in Arizona. It covers an area of about 18,661 square miles.
The largest county in square miles in Kansas is Sedgwick County, with an area of approximately 998 square miles.
The largest is Berkeley County with 1,228 square miles.
Shelby County is the largest county in Tennessee by square miles, covering an area of approximately 784 square miles.
Coconino County, Arizona has an area of 18,661 sq. miles.
The largest is Nye County with 18,147 square miles.
Osage County is the largest county in Oklahoma, measuring approximately 2,304 square miles.
It is Ware County with 903 square miles.
Keweenaw County - 5,966 square miles.
Worcester County with 1,513 square miles.