Classification: County
Located in: Illinois (IL)
Total Population (2000): 20121
Total Housing Units (2000): 8909
Land Area (square meters): 2058061147
Water Area (square meters): 51585223
Land Area (square miles): 794.621885
Water Area (square miles): 19.917167
Latitude (decimal degrees): 40.424406
Longitude (decimal degrees): -91.187696
FIPS Code: 17
Place FIPS Code: 67