Lewis County was split off from Oneida County by an Act of the Legislature on March 25, 1805. It is bordered on the east by Herkimer County, to the north by St. Lawrence, to the south by Oneida. It's western neighbors are Jefferson and Oswego Counties. Its 1,293 square miles contain 248.77 miles of county roads, 870.47 miles of township roads and 147.98 miles of state maintained highways. The county seat is Lowville.