County record · fips 17163 · Illinois
St. ClairIL
Democratic ×13 since 1976all 40 elections, 1868–2024
The Long Record
40 elections against the Illinois and national vote
2024 result
D+8.0
won by Democrats
Record since first cycle
32–8
Dem–Rep two-party wins
Voted with the winner
25/40
63% of its elections
Closest election
1880
D+0.3
this countyIllinoisnational (official)dot colour = two-party winner · hollow = tie or unknown total · click a dot to open that election
The Biggest Swings
Cycle-over-cycle change in the two-party margin, in points
| Election | Swing | Toward |
|---|---|---|
| 1876 | +110.5 pts | Democrats |
| 1872 | -80.2 pts | Republicans |
| 1928 | +30.0 pts | Democrats |
| 1932 | +27.1 pts | Democrats |
| 1968 | -25.7 pts | Republicans |
Who Lives Here
Census & ACS county profile, 2024
Population
253,694
College (BA+)
32%
Median income
$73,854
2024 dollars
Non-white
41%
Rural
14%
Age 65+
17%
Interpolated between Census/ACS anchors; income CPI-deflated to 2024. Demographics begin in 2000 — earlier cycles have returns only.
Neighbouring counties
Clinton, IL · Madison, IL · Monroe, IL · Randolph, IL · Washington, IL · St. Louis County, MO · St. Louis City, MO