Overview
- District ID
- il-sd-031
- State
- Illinois
- Chamber
- Upper chamber (state senate)
- District Code
- 031
- Land Area
- 141.3 sq mi
- Water Area
- 5.29 sq mi
Boundary
Boundary as GeoJSON
Source: U.S. Census Bureau TIGER/Line state legislative district boundaries.
Counties
| County | Overlap | Share of district land | Share of county land |
|---|
| Lake County | 141.29 sq mi | 100.0% | 31.8% |
Showing all 1 county
Places
Showing all 25 places
Overlapping Congressional Districts
| Congressional district | Population in both | Share of this district's population | Share of the congressional district's population | Share of this district's land |
|---|
| IL District 10 | 217,217 | 100.0% | 28.8% | 100.0% |
Source: U.S. Census Bureau 2020 blocks and 2025 block equivalency files (119th Congress, 2024 state legislative plans).
Voters
- Registered Voters
- 158,644
- Active Voters
- 143,765 (90.6%)
Party Registration
This state's voter file does not record party registration.
Turnout by Cycle
| Cycle | General | Democratic Primary | Republican Primary |
|---|
| 2025–2026 | 22,412 (14.1%) | 378 (0.2%) | 0 (0.0%) |
| 2023–2024 | 92,791 (58.5%) | 9,227 (5.8%) | 6,874 (4.3%) |
| 2021–2022 | 65,099 (41.0%) | 15,284 (9.6%) | 11,852 (7.5%) |
| 2019–2020 | 91,946 (58.0%) | 21,676 (13.7%) | 6,472 (4.1%) |
| 2017–2018 | 65,707 (41.4%) | 13,826 (8.7%) | 9,177 (5.8%) |
| 2015–2016 | 76,127 (48.0%) | 23,509 (14.8%) | 19,363 (12.2%) |
| 2013–2014 | 45,990 (29.0%) | 3,045 (1.9%) | 8,912 (5.6%) |
| 2011–2012 | 61,333 (38.7%) | 5,253 (3.3%) | 11,392 (7.2%) |
Turnout counts today's registered voters with a counted ballot in the cycle's elections (the odd and even year), as a share of today's registered voters. Voters who have since left the rolls are not counted.
Browse the voter list for this district (premium access; sign-in required)
Source: Civitech voter file snapshot as of 12/15/2025. These are registered voters, separate from the Census population figures. Counts under 10 are suppressed and shown as "<10".
Demographics
- Total Population
- 216,803 (± 2,052)
- Median Age
- 37.9
- Median Household Income
- $102,203 (± $2,943)
- High School Graduate or Higher (age 25+)
- 89.0%
- Bachelor's Degree or Higher (age 25+)
- 38.0%
Population by Age
| Group | People | Share |
|---|
| Under 18 | 51,627 | 23.8% |
| 18 to 64 | 134,833 | 62.2% |
| 65 and over | 30,343 | 14.0% |
Population by Race and Hispanic Origin
| Group | People | Share |
|---|
| Hispanic or Latino (any race) | 65,699 | 30.3% |
| White, not Hispanic | 111,152 | 51.3% |
| Black, not Hispanic | 16,861 | 7.8% |
| Asian, not Hispanic | 14,167 | 6.5% |
| American Indian / Alaska Native, not Hispanic | 165 | 0.1% |
| Native Hawaiian / Pacific Islander, not Hispanic | 43 | 0.0% |
| Some other race, not Hispanic | 1,113 | 0.5% |
| Two or more races, not Hispanic | 7,603 | 3.5% |
Source: U.S. Census Bureau, American Community Survey 2020-2024 ACS 5-year estimates (tables B01001, B01002, B01003, B03002, B15003, B19013) for this state legislative district. Estimates are survey-based; ± figures are 90% margins of error.
Citizen Voting Age Population
- Total Citizen Population
- 199,186
- Citizen Voting Age Population (CVAP)
- 148,679
Citizen Population by Race/Ethnicity
| Group | Citizens | Share |
|---|
| Non-Hispanic | 146,705 | 73.7% |
| Hispanic | 52,482 | 26.3% |
| White | 112,482 | 56.5% |
| Black | 16,794 | 8.4% |
| Asian | 11,661 | 5.9% |
| American Indian / Alaska Native | 141 | 0.1% |
| Native Hawaiian / Pacific Islander | 44 | 0.0% |
| Two or More Races | 600 | 0.3% |
Citizen Voting Age Population by Race/Ethnicity
| Group | CVAP | Share |
|---|
| Non-Hispanic | 117,833 | 79.3% |
| Hispanic | 30,846 | 20.7% |
| White | 92,802 | 62.4% |
| Black | 13,387 | 9.0% |
| Asian | 10,508 | 7.1% |
| American Indian / Alaska Native | 689 | 0.5% |
| Native Hawaiian / Pacific Islander | 42 | 0.0% |
| Two or More Races | 442 | 0.3% |
Source: Redistricting Data Hub / U.S. Census Bureau CVAP Special Tabulation (2020-2024 ACS 5-year).
