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Illinois State Senate District 21

Illinois State Senate District 21

Illinois · Latest: 2024↓ R+3.2 vs 2020

Shifted 3.2pp toward Republicans in 2024 — 217K residents

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Presidential margin · 2008 → 2024

Full history

  • 2008

    D+10.7

    Obama

  • 2012

    D+0.9

    Obama

  • 2016

    D+18.8

    Clinton

  • 2020

    D+25.2

    Biden

  • 2024

    D+22.0

    Harris

5 cycles · 2008 → 2024 · ↓ R+3.2 vs 2020

Who lives here

Full breakdown
  • White68.1%
  • Asian13.9%
  • Hispanic9.0%

Economy & age

Population
217K
Median age
39.2
Median income
$126K
+$42K vs U.S.
College+
63%
+26.9pp vs U.S.

Faith & language

Full detail
  • Catholic34.4%
  • Evangelical9.7%

77% English only23% Non-English

Similarity Explorer

Similar state senate districts

Reads like Illinois State Senate District 27, IL, Maryland State Senate District 33, MD, and Pennsylvania State Senate District 38, PA.
8 visible matches
Historian Query

Ask the Historian

Explore IL-SD-21's political evolution with the Historian
Race & Ancestry

Who Lives Here

A race-first Census view with ancestry expansion where source coverage is strong enough to support detail.
IL-SD-21Census ACS 2024Ancestry detail available
Census race profile
Major Census race and ethnicity groups shown as a share of total population.
Expand rows for ancestry detail
White (Non-Hispanic) 68.1%Asian 13.9%Hispanic 9.0%Black 5.0%Multiracial 3.7%
GroupIL-SD-21StateNational
▶White (Non-Hispanic)(13)
68.1%58.1%57.4%
▶Asian(6)
13.9%6.0%6.0%
▶Hispanic / Latino(18)
9.0%18.8%19.3%
▶Black / African American(13)
5.0%13.6%12.2%
Multiracial / Other
3.7%2.9%4.0%
▶Middle Eastern / North African(11)
2.2%—0.9%
▶Native American / Alaska Native(2)
0.3%0.6%0.9%
Method notes

Census treats race and Hispanic/Latino origin as separate questions. Race categories other than Hispanic reflect total populations (small Hispanic overlap in Black, Asian, AIAN, NHPI). “Multiracial / Other” is derived as a non-overlapping remainder.

Click rows to expand ancestry detail. Ancestry from ACS B04006, B03001, B02020, B02016. Totals may differ from race — individuals can report multiple ancestries.

Black / African American (estimated remainder) is derived as Black population share minus reported Sub-Saharan African and West Indian ancestry. It is shown as an estimated ancestry detail, not a standalone Census ancestry category.

MENA estimated from ancestry reporting — Census does not have a separate MENA race category. Not shown in bar (overlaps with other race groups).

Who lives in Illinois State Senate District 21? 217,256 residents as of the 2020 Census.

Demographic Comparison

Demographics

Read this geography's profile in three layers: local, state (where available), and national baseline.
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IL-SD-21 vs Illinois vs National217K residents

63% of adults hold a bachelor's degree — 30pp above the national average. Places with similar education levels vote D+25 on average nationally.

Population & electorate

Scale, voting-age share, and this geography's footprint inside the national electorate.

Total population
Local vs state vs U.S.
217K
local
217KState 12.7MNational 334.9M
Share of U.S. population
Local vs state vs U.S.
0.06%
local
0.06%National 100%
Voting-age population
Local vs state vs U.S.
77.1%
local
77.1%State 75.9%National 75.7%
Economic profile

Income, attainment, and ownership indicators that often shape coalition structure and turnout behavior.

Median household income
Local vs state vs U.S.
$125,645
local
$125,645State $84,845National $83,960
Poverty rate
Local vs state vs U.S.
6.0%
local
6.0%State 11.8%National 12.5%
College degree
Local vs state vs U.S.
62.5%
local
62.5%State 37.9%National 35.6%
Homeownership
Local vs state vs U.S.
73.2%
local
73.2%State 67.1%National 65.2%
Community profile

Age structure, language use, and nativity signals that explain how this geography differs from state and nation.

Median age
Local vs state vs U.S.
39.2 yrs
local
39.2 yrsState 39.1 yrsNational 39.1 yrs
Age 18–29
Local vs state vs U.S.
13.9%
local
13.9%State 15.8%National 15.7%
Age 65+
Local vs state vs U.S.
16.4%
local
16.4%State 17.0%National 17.0%
Foreign born
Local vs state vs U.S.
16.9%
local
16.9%State 14.7%National 14.1%
Non-English at home
Local vs state vs U.S.
22.8%
local
22.8%State 24.0%National 22.2%
English only
Local vs state vs U.S.
77.2%
local
77.2%State 76.0%National 77.8%
Voter Turnout

Turnout in IL-SD-21

Turnout % = votes cast ÷ voting-age population (VAP). Source: PL 94-171 2020 Census.
2024 Turnout
67.7%
vs Previous
-4.5pp
Voting-Age Pop
167,479
History
2008–2024
Contained geographies

Counties in IL-SD-21

Counties that overlap IL-SD-21.

Counties

(2)
DuPage84%Will16%

Other Illinois State Senate Districts

116 total
NameMargin ↓
IL-SD-07D+77.1
IL-SD-13D+72.6
IL-SD-03D+68.5
IL-SD-05D+67.0
IL-SD-06D+67.0
IL-SD-20D+62.7
IL-SD-17D+60.2
IL-SD-02D+57.1
IL-SD-04D+53.6
IL-SD-09D+52.2
IL-SD-15D+46.7
IL-SD-16D+46.0
IL-SD-39D+44.6
IL-SD-14D+38.0
IL-SD-12D+38.0
IL-SD-29D+33.4
IL-SD-30D+33.2
IL-SD-01D+30.1
IL-SD-52D+26.8
IL-SD-42D+21.0
IL-SD-11D+18.1
IL-SD-31D+18.1
IL-SD-22D+18.0
IL-SD-08D+17.8
IL-SD-27D+17.6
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