 The terrain slopes to the west, with its highest point, Briar Hill in Manistee National Forest at 1,706 (520m) ASL.According to the US Census Bureau, the county has a total area of 575.46 sqmi (1,490 km²), of which 565.00 sqmi (1,463 km²) is land and 10.46 sqmi (27.1 km²) (1.8%) is water.As of the 2000 United States Census, there were 30,484 people, 11,824 households, and 8,383 families in the county.