Peoria County is located in the U.S. state of Illinois. The 2020 United States Census listed its population at 181,830. Its county seat is Peoria. Peoria County is part of the Peoria metropolitan area.

This section needs expansion. You can help by adding to it. (August 2008)

Peoria County was formed in 1825 out of Fulton County. It was named for the Peoria, an Illiniwek people who lived there. It included most of the western valley of the Illinois River up to the Chicago river portage.

• 
  Peoria County at creation, with unorganized territory attached to it.
• 
  Peoria County 1826–1827. The newly created Mercer and Warren Counties were temporarily attached to Peoria.
• 
  Peoria County 1827–1830. The creation of Tazewell County left Peoria with only a small tract of unorganized territory east of the Illinois River, whose border was not defined.
• 
  In 1830, Warren County organized a government.
• 
  In 1831, Peoria County's present borders were established and Mercer County was attached to Warren.

According to the US Census Bureau, the county has a total area of 631 square miles (1,630 km), of which 619 square miles (1,600 km) is land and 11 square miles (28 km) (1.8%) is water. The county is drained by Spoon River, Kickapoo Creek, Elbow Creek, and Copperas Creek.

Peoria, Illinois
Climate chart (explanation)
J F M A M J J A S O N D     1.5     31 14     1.7     37 20     2.8     49 30     3.6     62 40     4.2     73 51     3.8     82 60     4     86 65     3.2     84 63     3.1     77 54     2.8     64 42     3     49 31     2.4     35 20 █ Average max. and min. temperatures in °F █ Precipitation totals in inches Source: The Weather Channel
Metric conversion J F M A M J J A S O N D     38     −1 −10     42     3 −7     72     9 −1     90     17 4     106     23 11     98     28 16     102     30 18     80     29 17     79     25 12     70     18 6     76     9 −1     61     2 −7 █ Average max. and min. temperatures in °C █ Precipitation totals in mm

In recent years, average temperatures in the county seat of Peoria have ranged from a low of 14 °F (−10 °C) in January to a high of 86 °F (30 °C) in July, although a record low of −27 °F (−33 °C) was recorded in January 1884 and a record high of 113 °F (45 °C) was recorded in July 1936. Average monthly precipitation ranged from 1.50 inches (38 mm) in January to 4.17 inches (106 mm) in May.

• Greater Peoria Mass Transit District
• Burlington Trailways
• Peoria Charter Coach Company
• List of intercity bus stops in Illinois

• Illinois Route 174
• Illinois Route 175

• General Wayne A. Downing Peoria International Airport (PIA), formerly Greater Peoria Regional Airport
• Mount Hawley Auxiliary Airport (3MY) – Peoria, Illinois

Historical population

Census	Pop.	Note	%±
1840	6,153		—
1850	17,547		185.2%
1860	36,601		108.6%
1870	47,540		29.9%
1880	55,355		16.4%
1890	70,378		27.1%
1900	88,608		25.9%
1910	100,255		13.1%
1920	111,710		11.4%
1930	141,344		26.5%
1940	153,374		8.5%
1950	174,347		13.7%
1960	189,044		8.4%
1970	195,318		3.3%
1980	200,466		2.6%
1990	182,827		−8.8%
2000	183,433		0.3%
2010	186,494		1.7%
2020	181,830		−2.5%
2023 (est.)	177,513		−2.4%
US Decennial Census 1790–1960 1900–1990 1990–2000 2010–2019

As of the 2020 United States Census, there were 181,830 people, including 73,253 households. The population density was 301.2 inhabitants per square mile (116.3/km). There were 83,034 housing units at an average density of 134.1 per square mile (51.8/km).

The racial makeup of the county was 73.5% white alone, 18.8% black or African American alone, 4.1% Asian alone, 0.4% American Indian alone, .1% Native Hawaiian and Other Pacific Islander alone, 3.1% listed two or more races, 5.1% Hispanic or Latino, and 69.4% were white and not of Hispanic or Latino origin. In terms of ancestry, per the 2010 US Census, 28.3% were German, 14.8% were Irish, 10.4% were English, and 5.5% were American.

Of the 75,793 households, 30.5% had children under the age of 18 living with them, 44.1% were married couples living together, 14.1% had a female householder with no husband present, 37.7% were non-families, and 31.0% of all households were made up of individuals. The average household size was 2.39 and the average family size was 3.00. The median age was 36.8 years.

The median income for a household in the county was $49,747 and the median income for a family was $63,163. Males had a median income of $51,246 versus $32,881 for females. The per capita income for the county was $28,157. About 10.3% of families and 14.5% of the population were below the poverty line, including 21.8% of those under age 18 and 7.8% of those age 65 or over.

• Glasford crater
• Jubilee College State Park
• WMBD World's Most Beautiful Drive (Grandview Drive/Prospect)
• Forest Park Nature Center
• Peoria Heights Tower Park
• Rock Island Trail

• Chillicothe
• Peoria (seat)
• West Peoria

• Lake Camelot
• Mossville
• Rome
• Smithville
• Trivoli

The cities of Peoria and West Peoria are considered independent from all of the townships within this county.

People from Peoria County other than in the city of Peoria:

• Chris Brackett, host of Arrow Affliction on The Sportsman Channel
• Mike Dunne, pitcher for several Major League Baseball teams
• Mary Emma Holmes (1839-1937), reformer, suffragist, and educator
• Bill Krieg, Major League Baseball player
• Lance (Henry) LeGault, TV and movie actor: Colonel Roderick Decker on The A-Team
• Zach McAllister, Major League Baseball player: Cleveland Indians pitcher
• Johnston McCulley, pulp fiction author: creator of Zorro
• Richard Pryor, Actor, Comedian
• David Ogden Stiers, actor, Major Charles Emerson Winchester III on M*A*S*H
• Josh Taylor, TV actor: Chris Kostichek on the soap opera Days of Our Lives
• Jim Thome, first baseman for several Major League Baseball teams

Peoria County is governed by an 18-member County Board which meets on the second Thursday of each month. Each member represents a district with roughly 10,000 residents.

District	Board Member	Residence	In office since	Party
1	Sharon K. Williams	Peoria	2012	Democratic
2	Camille Coates	Peoria	2022	Democratic
3	Betty Duncan	Peoria	2020	Democratic
4	Brandy Bryant	Peoria	2019	Democratic
5	James C. Dillon (Chair)	West Peoria	2006	Democratic
6	Dr. Eden Blair	Peoria	2019	Democratic
7	Phillip Salzer	Peoria	unknown	Democratic
8	Nathan Hoerr	Peoria	2022	Republican
9	Danny Phelan	Peoria Heights	2022	Democratic
10	Rob Reneau	Peoria	2018	Democratic
11	Linda E. Daley	Peoria	2019	Republican
12	Daniel Kelch	Edwards	2022	Republican
13	Terry Ruthland	Chillicothe	2022	Republican
14	Brian Elsasser	Princeville	1998	Republican
15	Steven B. Rieker	Peoria	2016	Republican
16	Matt Windish	Brimfield	2018	Republican
17	Jennifer Groves Allison	Peoria	2019	Democratic
18	Paul Rosenbohm	Peoria	2010	Republican

The County also elects an Auditor, Circuit Clerk, Coroner, County Clerk, Sheriff, State's Attorney, Regional Superintendent (Education), and Treasurer to four-year terms.

Office	Current Holder	In office since	Party
Auditor	Jessica Thomas	2018	Democratic
Circuit Clerk	Bobby Spears	2002	Democratic
Coroner	Jamie Harwood	2016	Democratic
County Clerk	Rachael Parker	2019	Democratic
Sheriff	Chris Watkins	2022	Republican
State's Attorney	Jodi Hoos	2019	Democratic
Regional Superintendent	Elizabeth Crider	2014	Democratic
Treasurer	Nicole Bjerke	2017	Republican

United States presidential election results for Peoria County, Illinois

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2024	36,896	46.62%	40,564	51.26%	1,678	2.12%
2020	38,252	45.55%	43,578	51.90%	2,143	2.55%
2016	35,633	45.05%	38,060	48.12%	5,409	6.84%
2012	36,774	46.90%	40,209	51.28%	1,428	1.82%
2008	34,579	42.32%	45,906	56.19%	1,219	1.49%
2004	41,051	49.60%	41,121	49.68%	599	0.72%
2000	36,398	47.39%	38,604	50.26%	1,810	2.36%
1996	30,990	41.82%	37,383	50.45%	5,729	7.73%
1992	30,718	37.77%	38,099	46.85%	12,511	15.38%
1988	37,605	51.35%	35,253	48.14%	372	0.51%
1984	45,607	55.02%	36,830	44.43%	462	0.56%
1980	47,815	57.26%	28,276	33.86%	7,419	8.88%
1976	46,526	56.65%	34,606	42.14%	991	1.21%
1972	50,324	64.49%	27,264	34.94%	444	0.57%
1968	37,021	49.96%	30,937	41.75%	6,147	8.29%
1964	33,327	41.30%	47,360	58.70%	0	0.00%
1960	45,529	53.77%	39,061	46.13%	86	0.10%
1956	50,888	62.72%	30,145	37.15%	108	0.13%
1952	49,245	59.09%	33,955	40.74%	139	0.17%
1948	35,018	52.78%	31,026	46.76%	308	0.46%
1944	34,171	50.81%	32,837	48.83%	243	0.36%
1940	34,911	45.21%	42,009	54.40%	301	0.39%
1936	25,425	33.96%	48,063	64.20%	1,377	1.84%
1932	25,166	39.50%	37,605	59.02%	945	1.48%
1928	31,024	56.50%	23,150	42.16%	739	1.35%
1924	25,243	58.55%	6,343	14.71%	11,526	26.74%
1920	24,541	66.00%	9,453	25.42%	3,188	8.57%
1916	18,615	48.38%	18,718	48.65%	1,145	2.98%
1912	9,229	41.91%	8,364	37.98%	4,427	20.10%
1908	10,828	52.47%	8,898	43.12%	909	4.41%
1904	11,868	62.02%	5,697	29.77%	1,570	8.20%
1900	10,700	51.82%	9,433	45.69%	514	2.49%
1896	10,486	52.70%	9,068	45.57%	344	1.73%
1892	7,266	45.63%	8,053	50.57%	605	3.80%

Prior to 1992, Peoria County, like most of central Illinois, was powerfully Republican. Usually, it only voted for Democratic Party presidential candidates when they won nationally by a landslide. It began trending away from the GOP in the mid-1980s, as evidenced when Ronald Reagan only carried it with 55 percent of the vote in 1984 even as he was winning reelection in a landslide nationally.

From 1992 onward, the county has backed the Democratic candidate in every presidential election, though never by a margin greater than 10 percent aside from 2008 when Illinoisan Barack Obama won it by nearly 14 points. This relative closeness in results was most evident in 2004 when the county backed John Kerry over George W. Bush by only 70 votes.

In Congress, Peoria County is represented by Democrat Eric Sorensen of Illinois's 17th congressional district and Republican Darin LaHood of the Illinois's 18th congressional district.

In the Illinois Senate, Peoria County is represented by Republican Win Stoller of the 37th Legislative District and Democrat Dave Koehler of the 46th Legislative District. In the Illinois House of Representatives, Peoria County is represented by Republican Ryan Spain of the 73rd Representative District, Republican Travis Weaver of the 91st Representative District and Democrat Jehan Gordon-Booth of the 92nd Representative District.

K-12 school districts include:

• Brimfield Community Unit School District 309
• Dunlap Community Unit School District 323
• Elmwood Community Unit School District 322
• Farmington Central Community Unit School District 265
• Illini Bluffs Community Unit School District 327
• Illinois Valley Central Unit School District 321
• Peoria School District 150
• Peoria Heights Community Unit School District 325
• Princeville Community Unit School District 326
• Stark County Community Unit School District 100
• Williamsfield Community Unit School District 210

Secondary school districts include:

• Limestone Community High School District 310

Elementary school districts include:

• Bartonville School District 66
• Hollis Consolidated School District 328
• Limestone Walters Community Consolidated School District 316
• Monroe School District 70
• Norwood Elementary School District 63
• Oak Grove School District 68
• Pleasant Hill School District 69
• Pleasant Valley School District 62

• National Register of Historic Places listings in Peoria County, Illinois

• Official website