'Mercer County, IL' definitions:
Mercer -- U.S. County in Illinois
From: Gazetteer 2000
Name :
Mercer -- U.S. County in Illinois
Population (2000) :
16957
Housing Units (2000) :
7109
Land area (2000) :
561.024464 sq. miles (1453.046630 sq. km)
Water area (2000) :
7.859359 sq. miles (20.355646 sq. km)
Total area (2000) :
568.883823 sq. miles (1473.402276 sq. km)
Located within :
Illinois (IL), FIPS 17
Location :
41.201226 N, 90.730320 W