Mercer County, 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.

File:Mercer_County_Illinois_1825.png|Mercer County at the time of its creation in 1825 File:Mercer County Illinois 1827.png|Mercer County in 1827, reduced to its present borders

Geography

According to the U.S. Census Bureau, the county has a total area of 569 sqmi, of which 561 sqmi is land and 7.5 sqmi (1.3%) is water.

Climate and weather

|Aledo, Illinois |11|29|1.27 |17|35|1.29 |26|47|2.43 |37|61|3.69 |48|72|3.92 |59|81|4.43 |62|84|4.21 |60|82|4.28 |51|75|3.31 |40|64|2.73 |28|47|2.50 |17|34|1.92 |access-date=January 27, 2011 In recent years, average temperatures in the county seat of Aledo have ranged from a low of 11 °F in January to a high of 84 °F in July, although a record low of -30 °F was recorded in February 1905 and a record high of 113 °F was recorded in July 1936. Average monthly precipitation ranged from 1.27 in in January to 4.43 in in June.

Major highways

• [[Image:US 67.svg|20px]] U.S. Highway 67
• [[Image:Illinois 17.svg|20px]] Illinois Route 17
• [[Image:Illinois 94.svg|20px]] Illinois Route 94
• [[Image:Illinois 135.svg|20px]] Illinois Route 135

Adjacent counties

• Rock Island County - north
• Henry County - east
• Knox County - southeast
• Henderson County - south
• Warren County - south
• Des Moines County, Iowa - southwest
• Louisa County, Iowa - west

Demographics

|align-fn=center 1790-1960 1900-1990 1990-2000 2010

2020 census

As of the 2020 census, the county had a population of 15,699. The median age was 45.1 years. 21.7% of residents were under the age of 18 and 22.3% of residents were 65 years of age or older. For every 100 females there were 100.4 males, and for every 100 females age 18 and over there were 99.6 males age 18 and over.

The racial makeup of the county was 94.0% White, 0.5% Black or African American, 0.2% American Indian and Alaska Native, 0.2% Asian,

There were 6,578 households in the county, of which 28.0% had children under the age of 18 living in them. Of all households, 54.2% were married-couple households, 18.1% were households with a male householder and no spouse or partner present, and 21.1% were households with a female householder and no spouse or partner present. About 27.7% of all households were made up of individuals and 14.1% had someone living alone who was 65 years of age or older.

There were 7,291 housing units, of which 9.8% were vacant. Among occupied housing units, 80.2% were owner-occupied and 19.8% were renter-occupied. The homeowner vacancy rate was 2.4% and the rental vacancy rate was 9.7%.

Racial and ethnic composition

2010 census

As of the 2010 United States census, there were 16,434 people, 6,734 households, and 4,724 families residing in the county.{{cite web |access-date=July 12, 2015 |archive-url=https://archive.today/20200213034214/http://factfinder.census.gov/bkmk/table/1.0/en/DEC/10_DP/DPDP1/0500000US17131 |archive-date=February 13, 2020 |url-status=dead |access-date=July 12, 2015 |archive-url=https://archive.today/20200212200156/http://factfinder.census.gov/bkmk/table/1.0/en/DEC/10_SF1/GCTPH1.CY10/0500000US17131 |archive-date=February 12, 2020 |url-status=dead |access-date=July 12, 2015 |archive-url=https://archive.today/20200213032119/http://factfinder.census.gov/bkmk/table/1.0/en/ACS/10_5YR/DP02/0500000US17131 |archive-date=February 13, 2020 |url-status=dead

Of the 6,734 households, 30.1% had children under the age of 18 living with them, 58.3% were married couples living together, 7.9% had a female householder with no husband present, 29.8% were non-families, and 25.8% of all households were made up of individuals. The average household size was 2.41 and the average family size was 2.88. The median age was 43.7 years.

The median income for a household in the county was $50,909 and the median income for a family was $62,025. Males had a median income of $46,136 versus $30,392 for females. The per capita income for the county was $25,332. About 8.2% of families and 9.3% of the population were below the poverty line, including 14.9% of those under age 18 and 7.2% of those age 65 or over.{{cite web |access-date=July 12, 2015 |archive-url=https://archive.today/20200213033028/http://factfinder.census.gov/bkmk/table/1.0/en/ACS/10_5YR/DP03/0500000US17131 |archive-date=February 13, 2020 |url-status=dead

Communities

Cities

• Aledo
• Keithsburg
• New Boston

Villages

• Alexis
• Joy
• Matherville
• North Henderson
• Reynolds (Part in Rock Island County)
• Seaton
• Sherrard
• Viola
• Windsor

Census-designated place

• Cable
• Eliza
• Hamlet
• Millersburg
• Preemption
• Swedona

Unincorporated communities

• Boden
• Burgess
• Gilchrist
• Mannon
• Marston
• Petersville
• Shale City
• Sunbeam
• Wanlock

Townships

Mercer County is divided into fifteen townships:

• Abington
• Duncan
• Eliza
• Greene
• Keithsburg
• Mercer
• Millersburg
• New Boston
• North Henderson
• Ohio Grove
• Perryton
• Preemption
• Richland Grove
• Rivoli
• Suez

Politics

Historically, Mercer County was a solidly Republican Yankee-influenced county, and before the Republican Party existed a stronghold of the Whig Party. The county never voted for a Democratic presidential candidate until Lyndon Johnson’s 1964 landslide over Barry Goldwater – the solitary break in Whig and Republican dominance occurring in 1912 when the GOP was mortally split and Progressive Theodore Roosevelt carried the county over conservative incumbent President William Howard Taft. After Johnson’s victory in the county, Mercer voted to being Republican between 1968 and 1984, but Reagan’s landslide in that election saw a swing to the Democrats that was capitalized upon by Michael Dukakis to carry the county in 1988. Between then and 2012, Mercer was solidly Democratic, but concern over declining economic opportunities in the “Rust Belt” caused a dramatic swing to populist Republican Donald Trump in 2016. Trump’s performance was the best by a Republican since Richard Nixon's 3,000-plus-county landslide in 1972.

Mercer County is located in Illinois's 17th Congressional District and is currently represented by Democrat Cheri Bustos. Within the Illinois House of Representatives, the county is located in the 74th district and is currently represented by Republican Daniel Swanson. The county is located in the 37th district of the Illinois Senate, and is currently represented by Republican Chuck Weaver.

Footnotes

References

1. (March 2025). "County Population Totals and Components of Change: 2020–2024". U.S. Department of Commerce.
2. "Mercer County, Illinois". [[United States Census Bureau]].
3. "Find a County". National Association of Counties.
4. United States Office of Management and Budget. "Update of Statistical Area Definitions and Guidance on Their Uses".
5. "Mercer County Fact Sheet".
6. "Population and Housing Unit Estimates Tables". United States Census Bureau.
7. "U.S. Decennial Census". United States Census Bureau.
8. "Historical Census Browser". University of Virginia Library.
9. "Population of Counties by Decennial Census: 1900 to 1990". United States Census Bureau.
10. "Census 2000 PHC-T-4. Ranking Tables for Counties: 1990 and 2000". United States Census Bureau.
11. "QuickFacts". [[United States Census Bureau]].
12. (2021). "2020 Decennial Census Demographic Profile (DP1)".
13. (2021). "2020 Decennial Census Redistricting Data (Public Law 94-171)".
14. (2023). "2020 Decennial Census Demographic and Housing Characteristics (DHC)".
15. "1980 Census of Population - General Population Characteristics - Illinois- Table 14 - Persons by Race and Table 16 (p. 18-28) - Total Persons and Spanish Origin Persons by Type of Spanish Origin and Race (p. 29-39)".
16. "1990 Census of Population - General Population Characteristics - Illinois - Table 6 - Race and Hispanic Orogin".
17. "P004: Hispanic or Latino, and Not Hispanic or Latino by Race – 2000: DEC Summary File 1 – Mercer County, Illinois".
18. "P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2010: DEC Redistricting Data (PL 94-171) – Mercer County, Illinois".
19. "P2: Hispanic or Latino, and Not Hispanic or Latino by Race – 2020: DEC Redistricting Data (PL 94-171) – Mercer County, Illinois".
20. included in the Asian category in the 1980 Census
21. included in the Asian category in the 1990 Census
22. not an option in the 1980 Census
23. not an option in the 1990 Census
24. Leip, David. "Dave Leip's Atlas of U.S. Presidential Elections".