County · Illinois
Mercer County, Illinois
Mercer County, Illinois. Mercer County had 15,229 residents in 2025 by the Census Bureau's estimate, down 3.0% since 2020, a steeper fall than Illinois's (−0.8%). It holds 33 places (12 cities, villages and boroughs, 15 towns and townships and 6 census-designated) and 4 census tracts. GEOID 17131.
Mercer County is one of the 4 counties of the Davenport-Moline-Rock Island, IA-IL metropolitan statistical area (the Census Bureau's July 2023 delineation).
Residents, July 2025 estimate
15,229
Census Bureau estimate (no margin published)
2020 Census count: 15,699 · ACS 2020-2024: 15,495
Median household income
$74,182
±$7,031 (90% margin)
Illinois: $83,390
Median home value
$146,700
±$7,887 (90% margin)
Illinois: $263,300
Median gross rent
$786
±$55 (90% margin)
Illinois: $1,274
How many people live in Mercer County, and is it growing?
The 2020 Census counted 15,699 residents in Mercer County. The Census Bureau estimates 15,229 for July 1, 2025, down 3.0% since 2020, a steeper fall than Illinois's (−0.8%). The 2020-2024 American Community Survey puts the population at 15,495 over 561 square miles of land.
| Measure | Mercer County | Illinois | Change since 2015-2019 |
|---|---|---|---|
| Total population | 15,495 | 12,694,798 | −94 |
| Households | 6,565±176 | 5,036,449 | no clear change |
| Average household size | 2.33±0.06 | 2.46 | no clear change |
| Housing units | 7,285±30 | 5,457,452 | −135 |
Mercer County's population since 2000
From 16,957 in 2000 to 15,229 in 2025: down 10.2%. The 2000, 2010 and 2020 figures are census counts. The 2005 figure is the Census Bureau's intercensal estimate, revised to fit the 2000 and 2010 counts and drawn on 2010 boundaries; 2015 and 2025 are July 1 estimates made from the census before them.
Source: The 2000, 2010 and 2020 Census counts and the Census Bureau's population estimates (intercensal 2000-2010, Vintage 2020, Vintage 2025) · Census population estimates
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); PEP Vintage 2025 (CO-EST2025); 2020 Census · Check it at data.census.gov
What cities and towns are in Mercer County?
Mercer County holds 33 places: 12 cities, villages and boroughs (incorporated places), 15 towns and townships (county subdivisions with their own government) and 6 census-designated places. The largest is Mercer Township with 3,841 residents (2025 estimate). Places that cross a county line are listed with the share of their 2020 residents who live in this county.
| Mercer Township | 3,964 | $71,042 |
|---|---|---|
| Aledo | 3,633 | $72,292 |
| Richland Grove Township | 2,333 | $106,630 |
| Preemption Township | 1,687 | $85,673 |
| Greene Township, Mercer County | 1,431 | $78,056 |
| New Boston Township | 1,179 | $48,125 |
| Rivoli Township | 1,039 | $55,875 |
| Viola | 869 | $72,500 |
| Matherville | 707 | $86,500 |
| Sherrard | 692 | $98,750 |
| Windsor, Mercer County | 668 | $59,333 |
| Keithsburg Township | 644 | $44,625 |
| Millersburg Township | 639 | $65,250 |
| Suez Township | 637 | $87,143 |
| New Boston | 613 | $60,662 |
| Keithsburg | 550 | $44,625 |
| Perryton TownshipGEOID 1713159182 | 449 | $61,389 |
| North Henderson TownshipGEOID 1713153806 | 400 | $73,167 |
| Eliza TownshipGEOID 1713123152 | 382 | $129,167 |
| Joy | 372 | $56,250 |
| Abington TownshipGEOID 1713100126 | 365 | $72,500 |
| Alexis | 793 | $66,250 |
| Duncan TownshipGEOID 1713120968 | 301 | not published |
| PreemptionGEOID 1761782 | 254 | $86,406 |
| Ohio Grove TownshipGEOID 1713155405 | 249 | $200,000 |
| SeatonGEOID 1768458 | 214 | $60,625 |
| North HendersonGEOID 1753793 | 162 | $74,231 |
| CableGEOID 1710305 | 117 | $104,375 |
| SwedonaGEOID 1774145 | 109 | not published |
| MillersburgGEOID 1749243 | 54 | not published |
| Reynolds | 498 | $76,458 |
| ElizaGEOID 1723139 | 25 | not published |
| HamletGEOID 1732473 | 21 | not published |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026); 2020 place-by-county parts · Check it at data.census.gov
Who lives in Mercer County?
The median resident of Mercer County is 44.7 years old; 20.8% are under 18 and 21.9% are 65 or older. The largest group is non-Hispanic white residents at 93.1%, then Hispanic or Latino residents (of any race) at 3.4%. 1.1% of residents were born outside the United States.
| Measure | Mercer County | Illinois | Change since 2015-2019 |
|---|---|---|---|
| Median age | 44.7±0.3 | 39.0 | no clear change |
| Under 18 years | 20.8%±0.3 pts | 21.8% | – |
| 65 years and over | 21.9%±0.1 pts | 17.0% | – |
| Hispanic or Latino (any race) | 3.4% | 18.8% | +1.0 pts |
| White alone, not Hispanic | 93.1%±0.4 pts | 58.1% | −2.2 pts |
| Black or African American alone, not Hispanic | 0.6%±0.3 pts | 13.3% | no clear change |
| Asian alone, not Hispanic | 0.4%±0.1 pts | 5.9% | no clear change |
| American Indian and Alaska Native alone, not Hispanic | 0.1%±0.1 pts | 0.1% | – |
| Native Hawaiian and Other Pacific Islander alone, not Hispanic | 0.0%±0.2 pts | 0.0% | – |
| Two or more races, not Hispanic | 2.4%±0.6 pts | 3.4% | – |
| Some other race alone, not Hispanic | 0.0%±0.1 pts | 0.4% | – |
| Born outside the United States | 1.1%±0.3 pts | 14.7% | no clear change |
| Speak a language other than English at home (age 5+) | 2.8%±0.6 pts | 24.0% | – |
| Civilian veterans (age 18+) | 8.4%±1.2 pts | 4.8% | – |
| With a disability | 13.0%±1.3 pts | 12.1% | – |
| No health insurance coverage | 4.6%±1.5 pts | 6.9% | no clear change |
| High school graduate or higher (age 25+) | 93.9%±1.4 pts | 90.5% | – |
| Bachelor's degree or higher (age 25+) | 20.9%±2.2 pts | 37.8% | +3.5 pts |
| Graduate or professional degree (age 25+) | 7.1%±1.4 pts | 15.3% | – |
| Moved from another state in the past year | 1.5%±0.6 pts | 1.6% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profiles DP02, DP05) · Check it at data.census.gov
What do households in Mercer County earn?
Half of Mercer County's 6,565 households earn less than $74,182 a year (±$7,031), against $83,390 in Illinois. In 2015-2019 it was $73,579 in 2024 dollars; the margins of error cannot tell the two periods apart. 8.9% of residents live below the poverty line.
| Measure | Mercer County | Illinois | Change since 2015-2019 |
|---|---|---|---|
| Median household income | $74,182±$7,031 | $83,390 | no clear change |
| Mean household income | $92,846±$4,653 | $115,638 | – |
| Per capita income | $39,391±$1,834 | $46,406 | +$3,371 |
| People below the poverty line | 8.9%±1.8 pts | 11.8% | no clear change |
| Children under 18 below the poverty line | 12.2%±4.5 pts | 15.1% | no clear change |
| Households receiving SNAP | 9.9%±2.0 pts | 13.8% | – |
| Households with a broadband subscription | 90.5%±2.0 pts | 90.8% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What does housing cost in Mercer County?
Owners occupy 83.8% of Mercer County's occupied homes and renters 16.2%. The median owner-occupied home is valued at $146,700 by its owner (±$7,887). The median renter pays $786 a month including utilities, and 26.0% of renters pay 35% or more of their income on rent.
| Measure | Mercer County | Illinois | Change since 2015-2019 |
|---|---|---|---|
| Median home value (owner-occupied) | $146,700±$7,887 | $263,300 | +$14,277 |
| Median gross rent | $786±$55 | $1,274 | no clear change |
| Renters paying 35% or more of income on rent | 26.0%±8.2 pts | 39.0% | no clear change |
| Median monthly owner costs, with a mortgage | $1,327±$39 | $1,987 | – |
| Owner-occupied homes | 83.8%±2.6 pts | 67.1% | +4.8 pts |
| Housing units | 7,285±30 | 5,457,452 | −135 |
| Homeowner vacancy rate | 0.2%±0.3 pts | 1.0% | – |
| Rental vacancy rate | 10.4%±6.7 pts | 5.0% | – |
| Single-family detached homes | 87.9%±2.0 pts | 58.2% | – |
| Mobile homes | 2.9%±0.8 pts | 2.3% | – |
| Built 2020 or later | 0.2%±0.2 pts | 0.7% | – |
| Built 1939 or earlier | 30.6%±2.6 pts | 20.2% | – |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP04) · Check it at data.census.gov
How many new homes is Mercer County building?
Builders took permits for 18 new housing units across Mercer County in 2025 (18 single-family), 1.2 per 1,000 residents.
Source: Building Permits Survey, annual county files 2019-2025, U.S. Census Bureau · Census Building Permits Survey
How do people in Mercer County get to work?
79.1% of Mercer County's workers drive alone and 10.1% work from home. The average trip to work takes 28.1 minutes. The unemployment rate in 2020-2024 averaged 3.2%.
| Measure | Mercer County | Illinois | Change since 2015-2019 |
|---|---|---|---|
| In the labor force (age 16+) | 60.8%±2.1 pts | 65.0% | – |
| Unemployment rate | 3.2%±1.0 pts | 5.8% | no clear change |
| Drove alone to work | 79.1%±2.9 pts | 65.9% | – |
| Carpooled | 8.0%±2.0 pts | 7.8% | – |
| Public transportation | 0.0%±0.5 pts | 5.8% | – |
| Walked | 2.4%±1.2 pts | 2.8% | – |
| Worked from home | 10.1%±1.9 pts | 15.9% | +6.0 pts |
| Mean travel time to work | 28.1 min±1.7 | 27.8 min | no clear change |
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) (Data Profile DP03) · Check it at data.census.gov
What are Mercer County's census tracts?
Mercer County is divided into 4 census tracts. Among those with a reliable estimate, median household income runs from $63,696 (Tract 402) to $90,729 (Tract 401).
Source: American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) · Check it at data.census.gov
How does Mercer County compare with Illinois's other counties?
| Measure | Rank |
|---|---|
| Population | 69th of 102 |
| Growth 2020-2025 | 68th of 102 |
| Residents per square mile | 79th of 102 |
| Median household income | 27th of 102 |
| Median home value | 41st of 102 |
| Median gross rent | 66th of 102 |
| Poverty rate | 83rd of 102 |
| Bachelor's degree or higher | 50th of 102 |
| Median age | 18th of 102 |
Source: PlainCities ranks from the American Community Survey 2020-2024 5-year estimates, U.S. Census Bureau (released January 2026) and PEP Vintage 2025 · How ranks are computed
How these figures are made: methodology and release checks · reading a margin of error · every state · corrections
Not on this page: crime, weather and schools for Mercer County are other agencies' records. Crime: the FBI's Crime Data Explorer · climate: NOAA's U.S. Climate Normals · schools: the National Center for Education Statistics' school search.