akashic
1876–2024
State Senate District 21·Illinois

Illinois 21st State Senate District changed direction in the last decade — D+13 in 2024.

One of Illinois's most Republican-leaning legislative districts

1876 — 2024·38 elections
IL
Latest
D+13
in 2024
Archetype
Recent convert
since the recent cycles
Population
155,534
2024 ACS

Illinois 21st State Senate District, Illinois: Recent convert district. In 2024, voted D+13%. Republican peak: R+67 in 1920.

Key facts

2024 presidential margin
D+13MIT Election Lab
Political archetype
Recent convertAkashic typology
Population
155,5342024 5-year
Median household income
$111,9812024 5-year
White (non-Hispanic)
64.7%2024 5-year
Black
5.4%2024 5-year
Hispanic / Latino
16.3%2024 5-year
Peak Democratic margin
D+17 in 2020MIT Election Lab
Peak Republican margin
R+67 in 1920MIT Election Lab
2024 results by constituent county
2 counties · 2 D · 0 R
R+60
D+60
One cell per constituent county. Ordered by 2024 D-vs-R margin (bluest first). Hover for county-level numbers.
38 presidential elections
Source · MIT Election Lab · ICPSR · VEST (precinct-level 2024).
YearWonMarginDemocraticRepublicanTotal
D
+12.5%
41,68232,14676,202
D
+17.5%
46,68932,48981,310
D
+14.0%
37,98627,91871,775
D
+1.3%
33,28232,39966,781
D
+10.9%
38,10030,51669,551
R
−9.5%
29,89336,19266,650
R
−12.9%
25,21932,94559,927
R
−10.2%
21,34726,78553,098
R
−16.6%
18,83528,89160,496
R
−38.8%
15,51035,33751,151
R
−51.1%
11,84136,86448,971
R
−39.3%
11,41629,66246,480
R
−39.4%
12,02428,42541,634
R
−49.6%
9,42628,03637,524
R
−39.8%
8,04920,27430,715
R
−18.5%
11,07216,09927,172
R
−37.4%
7,49516,48624,009
R
−58.3%
3,95815,07219,063
R
−49.8%
3,91611,71315,665
R
−45.8%
2,7757,58710,514
R
−35.9%
3,2866,98710,305
R
−34.0%
3,3486,83310,244
R
−11.6%
3,7694,7908,833
R
−14.4%
3,2454,3777,876
R
−42.3%
1,9104,7456,695
R
−63.2%
3562,9514,103
R
−66.7%
3952,2052,713
R
−30.7%
8991,7602,801
O
+13.1%
4112201,462
R
−34.8%
3818421,324
R
−44.7%
2617661,130
R
−29.8%
3887341,163
R
−37.6%
3347631,141
R
−5.8%
418473943
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Demographics

Race, ethnicity, and ancestry
Click any group to see the ancestries typically reported within it.
German
16.1%
Irish
13.0%
Italian
9.8%
Polish
9.7%
English
6.2%
American
2.6%
French
1.5%
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.
Age distribution by sex
Median age: 40.1 in this county, 39.1 nationally
Male
Age
Female
0.7%
85+
1.3%
2.2%
75–84
2.8%
4.9%
65–74
5.4%
6.6%
55–64
6.9%
6.4%
45–54
6.4%
7.0%
35–44
6.7%
6.3%
25–34
6.1%
4.2%
18–24
4.1%
8.5%
5–17
8.1%
2.8%
<5
2.7%
Source · American Community Survey 5-year estimates, 2024 release.
Median household income
2024 inflation-adjusted dollars
$111,981
State Senate District 21 ranks near the middle of US counties.
State Senate District 21$111,981
Illinois$83,390
United States$80,734
Source · American Community Survey 5-year estimates, 2024 release.
Poverty rate
All persons below federal poverty line
6.6%
Child poverty is below the national average.
Children under 187.2%
Working age (18–64)6.2%
Seniors (65+)9.1%
Source · American Community Survey 5-year estimates, 2024 release.
Language at home
Population aged 5 and older
70.8%
speak English only
Spanish11.6%
Other Indo-European11.2%
Asian & Pacific Islander5.2%
Other languages1.3%
Source · ACS 5-year estimates, 2024.
Religious adherents
Adherents per capita by tradition
Catholic & Orthodox
36.7%
Non-Christian
9.0%
Other Christian
7.5%
Mainline Protestant
6.4%
Methodist
1.8%
Pentecostal & Holiness
0.6%
Baptist
0.4%
Source · 2020 US Religion Census. Remaining 37.5% of residents not counted as adherents by any reporting body.

With a 2024 presidential margin of R+46.6, this downstate district ranks among the most reliably conservative constituencies in Illinois, reflecting the sharp rural-urban divide that defines the state's political geography.

The 2008 election was the turning point, when the Democratic candidate carried the district by eleven points. The 2024 margin was thirteen points, in line with the district's new direction.

The demographics suggest why. A population of 155,534, a 65% non-Hispanic-white share, and a median household income of $111,981 situate the district in the broader realignment patterns of recent cycles.

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.
State Senate District 21, Illinois. Akashic. https://akashic.app/sld-upper/17021/. Accessed May 20, 2026. License: CC BY 4.0.
License: CC BY 4.0

Frequently asked questions

How did State Senate District 21, Illinois vote in 2024?
In 2024, State Senate District 21, Illinois voted Democratic by 12.5 points (D+13), carried by the Democratic candidate. Out of 76,202 votes cast, 41,682 went Democratic and 32,146 went Republican.
What is State Senate District 21, Illinois's political archetype?
Akashic classifies State Senate District 21, Illinois as a "Recent convert" district based on its long-arc presidential voting pattern. Across 38 elections in the dataset, the district has voted Democratic 5 times, Republican 28 times, and other 1 times.
When did State Senate District 21, Illinois last vote Republican?
The most recent presidential election in which State Senate District 21, Illinois voted Republican was 2004.
How many people live in State Senate District 21, Illinois?
State Senate District 21, Illinois has a population of 155,534 according to the 2024 American Community Survey 5-year estimates from the US Census Bureau.
What is the median household income in State Senate District 21, Illinois?
Median household income in State Senate District 21, Illinois is $111,981 — above the national median of $80,734. The Illinois state median is $83,390.
What is the political history of State Senate District 21, Illinois?
Akashic tracks 38 presidential elections in State Senate District 21, Illinois from 1876 to 2024. Of those, 5 went Democratic and 28 went Republican. The district's archetype — "Recent convert" — captures the overall trajectory of that voting record.