According to the 2000 census , the county has a total area of 700.76 square miles ( 1,815.0 km2 ) , of which 693.98 square miles ( 1,797.4 km2 ) ( or 99.03 % ) is land and 6.78 square miles ( 17.6 km2 ) ( or 0.97 % ) is water .
693.98 square miles ( 1,797.4 km2 ) ( or 99.03 % ) is land and 6.78 square miles ( 17.6 km2 ) ( or 0.97 % ) is water .