Rock Island County, Illinois: Diversifying Metro county. In 2024, voted D+10%. Republican peak: R+54 in 1920.
Key facts
- 2024 presidential margin
- D+10MIT Election Lab
- Political typology
- Diversifying MetroAkashic typology
- Population
- 142,7572024 5-year
- Median household income
- $67,1592024 5-year
- White (non-Hispanic)
- 71.5%2024 5-year
- Black
- 11.4%2024 5-year
- Hispanic / Latino
- 14.2%2024 5-year
- Peak Democratic margin
- D+28 in 1964MIT Election Lab
- Peak Republican margin
- R+54 in 1920MIT Election Lab
- Most similar
- Costilla County, CO · similarity 0.99
2024 results by precinct
2024 precinct map of Rock Island CountyPrecinct-level 2024 presidential results for Rock Island County, with each precinct boundary colored by Democratic-vs-Republican margin.
—
Margin—
Turnout—
Harris +50Trump +50
Real precinct boundaries. Hover for vote totals.
presidential history
Presidential margin, 1876–2024
Democratic minus Republican, by election
| Year | Margin (D minus R) |
|---|---|
| 1876 | No data |
| 1880 | No data |
| 1884 | No data |
| 1888 | No data |
| 1892 | −10.6% |
| 1896 | −21.6% |
| 1900 | −25.9% |
| 1904 | −45.4% |
| 1908 | −23.4% |
| 1912 | +10.5% |
| 1916 | −17.3% |
| 1920 | −54.4% |
| 1924 | −47.5% |
| 1928 | −30.9% |
| 1932 | +7.5% |
| 1936 | +25.0% |
| 1940 | +15.7% |
| 1944 | +11.3% |
| 1948 | +5.0% |
| 1952 | −8.3% |
| 1956 | −3.6% |
| 1960 | +1.9% |
| 1964 | +27.6% |
| 1968 | +5.8% |
| 1972 | −7.1% |
| 1976 | +2.8% |
| 1980 | −6.6% |
| 1984 | +6.7% |
| 1988 | +18.8% |
| 1992 | +19.7% |
| 1996 | +23.3% |
| 2000 | +19.6% |
| 2004 | +14.6% |
| 2008 | +24.6% |
| 2012 | +21.8% |
| 2016 | +8.3% |
| 2020 | +12.1% |
| 2024 | +9.6% |
DemocraticRepublican
38 presidential elections
| Year | Won | Margin | Democratic | Republican | Total |
|---|---|---|---|---|---|
| D | 34,126 | 28,061 | 63,458 | ||
| D | 36,691 | 28,603 | 66,947 | ||
| D | 32,298 | 26,998 | 63,994 | ||
| D | 39,157 | 24,934 | 65,217 | ||
| D | 42,210 | 25,364 | 68,401 | ||
| D | 39,880 | 29,663 | 69,972 | ||
| D | 37,957 | 25,194 | 65,095 | ||
| D | 34,822 | 20,626 | 60,955 | ||
| D | 37,412 | 23,212 | 72,039 | ||
| D | 40,174 | 27,412 | 67,901 | ||
| D | 40,208 | 35,121 | 75,672 | ||
| R | 30,045 | 34,788 | 71,775 | ||
| D | 35,994 | 34,007 | 71,261 | ||
| R | 32,529 | 37,548 | 70,330 | ||
| D | 34,506 | 30,404 | 70,140 | ||
| D | 41,759 | 23,714 | 65,473 | ||
| D | 33,812 | 32,534 | 66,454 | ||
| R | 29,145 | 31,342 | 60,605 | ||
| R | 27,879 | 32,933 | 60,912 | ||
| D | 24,542 | 22,192 | 47,211 | ||
| D | 30,102 | 23,980 | 54,262 | ||
| D | 35,240 | 25,629 | 61,101 | ||
| D | 32,741 | 19,487 | 53,027 | ||
| D | 24,676 | 21,205 | 46,549 | ||
| R | 14,334 | 27,246 | 41,776 | ||
| R | 3,631 | 20,563 | 35,647 | ||
| R | 5,208 | 21,908 | 30,719 | ||
| R | 10,914 | 16,169 | 30,322 | ||
| O | 3,997 | 2,394 | 15,289 | ||
| R | 4,739 | 8,196 | 14,781 | ||
| R | 2,156 | 8,152 | 13,203 | ||
| R | 4,786 | 8,299 | 13,556 | ||
| R | 4,692 | 7,323 | 12,191 | ||
| R | 4,034 | 5,052 | 9,645 | ||
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Demographics
2024 ACS
Race, ethnicity, and ancestry
Click any group to see the ancestries typically reported within it.
German
18.7%
Irish
10.6%
English
9.3%
American
3.5%
Italian
2.7%
Polish
1.6%
Scottish
1.5%
African American
9.1%
Multiple ancestry combinations reported; no single grouping above 1%.
American Indian, Alaska Native, Native Hawaiian, and Pacific Islander combined.
Source · American Community Survey 5-year estimates, 2024 release. Hispanic/Latino is an ethnicity that overlaps the race categories, so these shares can total more than 100%. Ancestry is a self-reported, multiple-response item; ancestry percentages do not sum to the parent race percentage.
2024 ACS
Age distribution by sex
Median age: 40.3 in this county, 39.1 nationally
Male
Age
Female
85+
75–84
65–74
55–64
45–54
35–44
25–34
18–24
5–17
<5
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Median household income
Inflation-adjusted dollars
$67,159
Rock Island County ranks near the middle of US counties.
Rock Island County$67,159
Illinois$83,390
United States$80,734
Rock Island County ranks near the middle of US counties by median household income.
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Poverty rate
All persons below federal poverty line
15.5%
Children face moderate poverty.
Children under 1823.7%
Working age (18–64)13.5%
Seniors (65+)9.4%
Source · American Community Survey 5-year estimates, 2024 release.
2024 ACS
Language at home
Population aged 5 and older
86.2%
speak English only
Spanish7.3%
Other Indo-European3.1%
Other languages2.0%
Asian & Pacific Islander1.4%
Source · ACS 5-year estimates, 2024.
2020 religion census
Religious adherents
Adherents per capita by tradition
Source · 2020 US Religion Census. Remaining 68.4% of residents not counted as adherents by any reporting body.
Rock Island anchors Illinois's Quad Cities metro along the Iowa border, where a unionized manufacturing heritage and a diverse urban core in Rock Island and Moline have kept the county reliably left of center in statewide contests.
The Democratic margin here reached twenty-eight points in 1964. Between 2020 and 2024 the county moved three points toward the Republican candidate; the 2024 margin was ten points.
A population of 142,757, a 72% non-Hispanic-white share, and a median household income of $67,159 describe the county. The county's voting pattern over the last decade is most similar to that of Costilla County and Genesee County.
Most similar counties
Compare two places, side by side
Twelve curated comparisons line up election history, demographics, and the divergence story for two places at a glance. Browse all comparisons →
Cite this page
All citations released under CC BY 4.0. Attribution: Akashic Intelligence.
Rock Island County, Illinois. Akashic. https://akashic.app/county/17161/. Accessed May 20, 2026. License: CC BY 4.0.
License: CC BY 4.0
More diversifying metro counties
Frequently asked questions
How did Rock Island County, Illinois vote in 2024?
In 2024, Rock Island County, Illinois voted Democratic by 9.6 points (D+10), carried by the Democratic candidate. Out of 63,458 votes cast, 34,126 went Democratic and 28,061 went Republican.
What is Rock Island County, Illinois's political typology?
Akashic places Rock Island County, Illinois in the "Diversifying Metro" typology — Mid-size metropolitan counties growing more diverse and trending Democratic. The typology is a data-driven cluster built from vote share, vote swing, race and ethnicity, income, language spoken at home, religion, and ancestry. Across 38 elections in the dataset, the county has voted Democratic 20 times, Republican 13 times, and other 1 times.
When did Rock Island County, Illinois last vote Republican?
The most recent presidential election in which Rock Island County, Illinois voted Republican was 1980.
How many people live in Rock Island County, Illinois?
Rock Island County, Illinois has a population of 142,757 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in Rock Island County, Illinois?
Median household income in Rock Island County, Illinois is $67,159 — below the national median of $80,734. The Illinois state median is $83,390.
What is the political history of Rock Island County, Illinois?
Akashic tracks 38 presidential elections in Rock Island County, Illinois from 1876 to 2024. Of those, 20 went Democratic and 13 went Republican. The county's typology — "Diversifying Metro" — captures where that record, its demographics, and its recent swing place it among American communities.