Mercer

Formed January 13, 1825 (43^rd county)

Mercer County (15,694), Aledo (3,636)

A classic stone courthouse built in 1894 serves Mercer County.  It is located on a square on 3^rd Street, 2^nd Avenue, 4^th Street, and College Avenue.  Illinois State Highway 94 is College Street in this part of Aledo.  Mifflin Emien Bell provided the Romanesque style designs.  The building features a tower and a veteran’s plaque.  The grounds have veteran memorials and a Theodore Roosevelt statue.  Mercer County is created on January 13, 1825, as the 43^rd county, and taken from the “Militia Tract.”  Boston (1835), Millersburg (1837), and Aledo (1857) have all served as county seat.  Revolutionary War General Hugh Mercer is the source of the county’s name.  The county seat gets its name from Aledo, Spain. 

Mercer County government consists of a sheriff and 10 Commissioners.  Twenty Circuit Court Judges serve Mercer, Henry, Rock Island, and Whiteside counties.  The county is in western Illinois on the border with Iowa.  The Mississippi River forms its western border.  Davenport, Iowa is north and Peoria, Illinois is southeast of the county.  The county center is 3.8 miles East of Aledo.  The county is surrounded clockwise by Rock Island, Henry, Knox, Henderson, and Warren counties and Iowa. 

The area of the county is 561 square miles.  It is 45 out of 102 in the state.  It ranks 69 out of 102 in population in the state.  It has a density of 28.0 persons per square mile making it 79 out of 102 in the state.  Mercer County has 56.5% of its population in its incorporated areas.  United States Highway 67 crosses the county north to south from Rock Island County to Warren County.  The county looks like a box of popcorn lying on its side.  Aledo is located slightly west of center in the county.  Aledo is the county seat and the largest city.  It is 23.2% of the county population.  The county seat is pronounced A-LEE-DOE.  This county is in the Davenport-Moline-Rock Island Metropolitan Statistical Area.