Illinois House of Representatives seat · lines in effect since 2022
Illinois Representative District 42
A district of about 109,000 people, 57% of adults with a bachelor's degree. It votes D+22.5 relative to the nation for president.
Where it sits among all 118 seats
Every Illinois House of Representatives seat by partisan lean, from most Democratic to most Republican. Lean is the seat's presidential vote on current lines, relative to the nation.
Democratic
Source: 99chambers: 2024 and 2020 presidential results on current lines, relative to the nation (2024 weighted 3:1)Updated Oct 16, 2026, 5:19 AM ET
Every race on these lines
Results recomputed from precinct returns as if today's boundaries had always existed, so years compare like for like.
| 2016 | 2018 | 2020 | 2022 | 2026 | |
|---|---|---|---|---|---|
| U.S. Senate | D+5.7 | No race | D+18.9 | No race | No race |
| Governor | No race | D+5.2 | No race | No race | No race |
| Illinois House of Representatives | No race | No race | No race | D+16.5 | D+32.6 |
Outlined: the race for this seat itselfBlank: no race that year
Source: 99chambers results archive: precinct results allocated to current lines; 2026: civicAPIUpdated Nov 7, 2026, 3:01 PM ET
Who lives here, compared
Grey bars show the spread of all 118 seats. Small marks are other seats in Illinois. The black marker is District 42.
Higher than 86% of seats.
Lower than 57% of seats.
Lower than 59% of seats.
Lower than 61% of seats.
Higher than 79% of seats.
Denser than 64% of seats.
Source: Census Bureau, American Community Survey 2020–2024 5-year estimates, allocated to current linesUpdated Oct 13, 2026, 5:06 AM ET
Seats most like this one
Nearest seats on demographics, density and lean. 1 of the 4 flipped this year.
District 8158% college gradsD+22.3Held DDistrict 54
53% college gradsD+20.9Held DDistrict 45
60% college gradsD+14.1Held DDistrict 47
60% college gradsD+11.2Flipped D
Source: Census Bureau, American Community Survey 2020–2024 5-year estimates, allocated to current lines; 99chambers: 2024 and 2020 presidential results on current lines, relative to the nation (2024 weighted 3:1)Updated Oct 16, 2026, 5:19 AM ET
Who has held it
These lines took effect in 2022.
- Margaret A. Delarosa (D)
2027– · Won 2026 by 32.6 - Terra Costa Howard (D)
2023–2027 · Won 2022 by 16.5, 2024 by 75.8
Source: Past results: 99chambers results archive (MEDSL, Klarner, state election offices)