Map of Mercer County, Illinois

Mercer County is a county in Illinois. According to the 2010 census, it had a population of 16,434. Its county seat is Aledo.

Mercer County is included in the Davenport–Moline–Rock Island, IA-IL Metropolitan Statistical Area.

Mercer County overview:
Name:	Mercer County
FIPS code:	17-131
State:	Illinois
Founded:	January 13, 1825
Named for:	Hugh Mercer
Seat:	Aledo
Largest city:	Aledo
Total Area:	569 sq mi (1,470 km²)
Land Area:	561 sq mi (1,450 km²)
Total Population:	15,699
Population Density:	28/sq mi (11/km²)
Time zone:	UTC−6 (Central)
Summer Time Zone (DST):	UTC−5 (CDT)
Website:	www.mercercountyil.org

Mercer County location map. Where is Mercer County?

Mercer County location on the U.S. Map. Where is Mercer County. — Location of Mercer County in the the United States.

Mercer County location on the Illinois map. Where is Mercer County. — Location of Mercer County in Illinois.

History

Mercer County is named for Hugh Mercer (1726–1777), a physician and general during the American Revolution who died from wounds suffered at the Battle of Princeton.

In May 1812, Congress passed an act which set aside lands in Arkansas, Michigan, and Illinois as payment to volunteer soldiers in the War of 1812. Mercer County was part of this “Military Tract.”

Seven years after Illinois became a state, Mercer County was founded. It was formed from unorganized territory near Pike County on January 13, 1825. Although the county had been created, its government was not organized for several years; for administration purposes it was attached first to Schuyler County (until 1826), then to Peoria (until 1831), and finally to Warren County. The organization of the county government was finally completed in 1835, after a large influx of settlers following the Black Hawk War.

Mercer County at the time of its creation in 1825
Mercer County in 1827, reduced to its present borders

Mercer County Road Map

Mercer CountyStreet Map. — Street map of Mercer County, Illinois. Source: OpenStreetMap (OSM)

Mercer CountyMap — Mercer Countypolitical map.

Geography

According to the U.S. Census Bureau, the county has a total area of 569 square miles (1,470 km), of which 561 square miles (1,450 km) is land and 7.5 square miles (19 km) (1.3%) is water.

Climate and weather

In recent years, average temperatures in the county seat of Aledo have ranged from a low of 11 °F (−12 °C) in January to a high of 84 °F (29 °C) in July, although a record low of −30 °F (−34 °C) was recorded in February 1905 and a record high of 113 °F (45 °C) was recorded in July 1936. Average monthly precipitation ranged from 1.27 inches (32 mm) in January to 4.43 inches (113 mm) in June.