Pierce County, Washington, USA - 1,806 square miles (of this, 128 square miles is water).
Lycoming County with an area of 1,244 square miles.
It is Ware County with 903 square miles.
Keweenaw County - 5,966 square miles.
Shelby County is the largest county in Tennessee by square miles, covering an area of approximately 784 square miles.
Worcester County with 1,513 square miles.
Jackson County in Florida covers approximately 917 square miles.
The are of Fulton County, Georgia is 535 square miles.
Fulton County, GA's area is 534.75 square miles.
Baldwin County, AL's area is 2,027 square miles.
Fayette County, Tennessee is 706 square miles.
Loudoun County, Virginia has a land area of approximately 520 square miles.
Osage County: 2,251 square miles.