Mercer County, Illinois
Mercer County: county in Illinois, United States.
About
Mercer County is a county located in the U.S. state of Illinois. As of the 2010 census, the population was 16,434 and a population density of 11 people per km². After 10 years in 2020 county had an estimated population of 15,225 inhabitants. Its county seat is Aledo. The county was created 201 years ago in 1825.
County Snapshot
Mercer County at a glance
Mercer County currently has 2 quality-checked populated place pages linked on MapSof, making it easier to jump from the county overview into local city pages.
Mapped populated places
2
These counts use a stricter populated-place filter so the main lists stay focused on real city and town pages.
Illinois counties
102
Open related pagesLargest city
AledoPopulation 3,383
Top linked places
Quick Facts about Mercer County
| Population | 15,225 (2020) |
| Country | United States of America |
| State | Illinois (United States) |
| Different from | Mercer County, Mercer County, Mercer County, Mercer County, Mercer County, Mercer County, Mercer County |
| Area | 1453 km2 |
| Water as percent of area | 1.3% |
| Land as percent of area | 98.7% |
| Latitude & Longitude | 41.2053,-90.7414 |
| Named for | Hugh Mercer |
| Capital | Aledo |
| Establishment | January 13, 1825 |
| Time Zone | America/Chicago |
| Local time | 06:17:46 (23rd September 2026) |
| Density | 10 Pop. per km² as of 2020 |
| Population growth | -7.36% (2010-2020) |
| Weather | 66℉ Mostly Sunny 7-days weather |
Geography
Mercer County is located at 41°12'19"N 90°44'29"W (41.2053400, -90.7414100). It has 7 neighbors: Des Moines County, Louisa County, Henderson County, Henry County, Knox County, Rock Island County and Warren County.
Mercer County map
icon to open full mode. View satellite images
The largest city of Mercer County is Aledo with a population of 3,383. . See all Mercer County cities & populated places.
Mercer County Populated Places
Cities, towns, neighborhoods & other populated places in Mercer County.
| City Name | Population | Title |
|---|---|---|
| Aledo | 3,383 | City in Mercer County, Illinois, United States |
| Preemption | 1,628 | Township in Mercer County, Illinois |
Weather
Mostly sunny, with a high near 66.
7-Day ForecastOfficial website of Mercer County
Official WebsiteDemographics
According to census records, the population of Mercer County decreased by 7.36% in 10 years.
| Year | Population | % Change | Method |
|---|---|---|---|
| 2010 | 16,434 | - | census |
| 2011 | 16,316 | -0.72% | estimation process |
| 2012 | 16,163 | -0.94% | estimation process |
| 2013 | 16,075 | -0.54% | estimation process |
| 2014 | 15,901 | -1.08% | estimation process |
| 2015 | 15,746 | -0.97% | estimation process |
| 2016 | 15,602 | -0.91% | estimation process |
| 2017 | 15,608 | 0.04% | estimation process |
| 2018 | 15,551 | -0.37% | estimation process |
| 2019 | 15,437 | -0.73% | estimation process |
| 2020 | 15,225 | -1.37% | estimation process |
People born in Mercer County (4)
People born in Mercer County, including United States federal judge Orie Leon Phillips, mayor William Arthur Ginn, academic Ida Morey Riley, .
More notable people
- Oliver W. Stewart he was born in 22/05/1867
Other places with the same name (7)
- Mercer County, New Jersey county in West Virginia, United States. with a population of 367,239 people.
- Mercer County, Pennsylvania county in Pennsylvania, United States. with a population of 108,545 people.
- Mercer County, West Virginia county in West Virginia, United States. with a population of 58,258 people.
- Mercer County, Ohio county in Ohio, United States. with a population of 41,274 people.
- Mercer County, Kentucky county in Kentucky, United States. with a population of 21,889 people.
- Mercer County, North Dakota county in North Dakota, United States. with a population of 8,174 people.
- Mercer County, Missouri county in Missouri, United States. with a population of 3,558 people.
Illinois Other Counties (more counties)
| County Name | Population | Title |
|---|---|---|
| Cook County | 5,108,284 | County in Illinois, United States |
| Chicago | 2,677,643 | The third most populous city in the United States and the center of the Chicago metropolitan area. |
| DuPage County | 917,481 | County in Illinois, United States |
| Lake County | 693,593 | County in Oregon, United States |
| Will County | 688,726 | County in Illinois, United States |
| Kane County | 531,010 | County in southern Utah, United States |
| McHenry County | 305,888 | County in Illinois, United States |
| Winnebago County | 281,295 | County in Illinois, United States |
| Madison County | 262,635 | County in Montana, United States |
| Saint Clair County | 258,046 | The County of St. |
| Champaign County | 209,192 | County in Illinois, United States |
| Aurora | 196,383 | The second most populous city in Illinois. |
| Sangamon County | 193,882 | County in Illinois, United States |
| Peoria County | 177,652 | County in Illinois, United States of America |
| McLean County | 171,256 | County in North Dakota, United States |
| Naperville | 147,986 | The second most populous city in Illinois. |