Warren County, Illinois
|Warren County, Illinois|
Location in the state of Illinois
Illinois's location in the U.S.
543.05 sq mi (1,406 km²)
542.40 sq mi (1,405 km²)
0.65 sq mi (2 km²), 0.12%
34/sq mi (13/km²)
Warren County is a county located in the U.S. state of Illinois. According to the 2010 census, it has a population of 17,707, which is a decrease of 5.5% from 18,735 in 2000. Its county seat is Monmouth.
Warren County was organized in 1825 out of Pike County. Pike County, consisted of all portions of state North and West of the Illinois River before 1825. Henderson County was formed in 1841 from the western area of Warren County. Warren County was named for Dr. Joseph Warren, killed at the Battle of Bunker Hill in 1775. He is believed to have been the first officer to fall in the Revolutionary War.
The current courthouse, constructed of red Portage stone, was completed in 1895.
Between 1831 and 1835, Mercer County was temporarily attached to Warren until it could organize its own county government.
According to the 2010 census, the county has a total area of 543.05 square miles (1,406.5 km2), of which 542.40 square miles (1,404.8 km2) (or 99.88%) is land and 0.65 square miles (1.7 km2) (or 0.12%) is water.
Adjacent counties 
- Mercer County (north)
- Knox County (east)
- Fulton County (southeast)
- McDonough County (south)
- Henderson County (west)
|IL Counties 1900-1990
As of the census of 2000, there were 18,735 people, 7,166 households, and 4,966 families residing in the county. The population density was 34 people per square mile (13/km²). There were 7,787 housing units at an average density of 14 per square mile (6/km²). The racial makeup of the county was 95.60% White, 1.59% Black or African American, 0.18% Native American, 0.34% Asian, 0.10% Pacific Islander, 1.10% from other races, and 1.10% from two or more races. 2.71% of the population were Hispanic or Latino of any race. 18.7% were of American, 17.1% German, 13.8% English, 12.2% Irish and 9.0% Swedish ancestry.
The largest self-reported ancestry groups in Warren County as of 2010 are:
There were 7,166 households out of which 29.80% had children under the age of 18 living with them, 56.50% were married couples living together, 8.80% had a female householder with no husband present, and 30.70% were non-families. 26.70% of all households were made up of individuals and 12.70% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 2.94.
In the county the population was spread out with 23.20% under the age of 18, 12.40% from 18 to 24, 24.50% from 25 to 44, 23.60% from 45 to 64, and 16.30% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 93.80 males. For every 100 females age 18 and over, there were 91.10 males.
The median income for a household in the county was $36,224, and the median income for a family was $42,437. Males had a median income of $30,365 versus $20,453 for females. The per capita income for the county was $16,946. About 6.80% of families and 9.20% of the population were below the poverty line, including 11.50% of those under age 18 and 7.00% of those age 65 or over.
- U.S. Highway 34
- U.S. Highway 67
- Illinois Route 94
- Illinois Route 116
- Illinois Route 135
- Illinois Route 164
Law enforcement 
- Warren County Sheriff's Office
Warren County/Monmouth Auxiliary Police Corps
Cities and towns 
Unincorporated communities 
- Cold Brook
- Shanghai City
- Swan Creek
Warren County is divided into these townships:
Climate and weather 
|Climate chart (explanation)|
In recent years, average temperatures in the county seat of Monmouth have ranged from a low of 15 °F (−9 °C) in January to a high of 85 °F (29 °C) in July, although a record low of −27 °F (−33 °C) was recorded in February 1905 and a record high of 110 °F (43 °C) was recorded in July 1936. Average monthly precipitation ranged from 1.62 inches (41 mm) in January to 4.33 inches (110 mm) in July.
See also 
- "Warren County QuickFacts". United States Census Bureau. Retrieved 2011-11-05.
- "Find a County". National Association of Counties. Retrieved 2011-06-07.
- White, Jesse. Origin and Evolution of Illinois Counties. State of Illinois, March 2010. 
- "Census 2010 U.S. Gazetteer Files: Counties". United States Census. Retrieved 2011-11-05.
- "American FactFinder". United States Census Bureau. Retrieved 2008-01-31.
- "Monthly Averages for Monmouth, Illinois". The Weather Channel. Retrieved 2011-01-27.
|Henderson County||Knox County|
|McDonough County||Fulton County|