Illinois State Senate District 45

State Legislative District Profile (Upper Chamber)

Overview

District ID
il-sd-045
State
Illinois
Chamber
Upper chamber (state senate)
District Code
045
Land Area
2,862.5 sq mi
Water Area
48.3 sq mi

Boundary

Boundary of Illinois State Senate District 45

Boundary as GeoJSON

Source: U.S. Census Bureau TIGER/Line state legislative district boundaries.

Counties

CountyOverlapShare of district landShare of county land
Jo Daviess County600.92 sq mi21.0%100.0%
Stephenson County564.25 sq mi19.7%100.0%
Ogle County563.88 sq mi19.7%74.3%
Carroll County445.41 sq mi15.6%100.0%
Winnebago County389.08 sq mi13.6%75.8%
DeKalb County177.00 sq mi6.2%28.0%
Boone County121.94 sq mi4.3%43.4%

Showing all 7 counties

Places

PlaceOverlapShare of district landShare of place land
Lake Carroll CDP13.55 sq mi0.5%100.0%
Machesney Park village12.13 sq mi0.4%95.6%
Freeport city11.88 sq mi0.4%100.0%
The Galena Territory CDP11.01 sq mi0.4%100.0%
Roscoe village10.26 sq mi0.4%100.0%
Loves Park city7.75 sq mi0.3%47.5%
Rockton village6.86 sq mi0.2%100.0%
South Beloit city6.14 sq mi0.2%99.6%
Rockford city5.51 sq mi0.2%8.4%
Byron city4.65 sq mi0.2%100.0%
Galena city4.49 sq mi0.2%97.2%
Davis Junction village4.20 sq mi0.1%100.0%
Apple Canyon Lake CDP3.72 sq mi0.1%100.0%
East Dubuque city2.74 sq mi0.1%95.4%
Willow Lake CDP2.73 sq mi0.1%100.0%
Lena village2.65 sq mi0.1%100.0%
Savanna city2.62 sq mi0.1%100.0%
Genoa city2.59 sq mi0.1%99.8%
Thomson village2.22 sq mi0.1%100.0%
Lake Summerset CDP2.12 sq mi0.1%100.0%
Mount Carroll city2.00 sq mi0.1%100.0%
Winnebago village1.93 sq mi0.1%100.0%
Oregon city1.93 sq mi0.1%100.0%
Menominee village1.91 sq mi0.1%100.0%
Stockton village1.88 sq mi0.1%100.0%

Showing top 25 of 67 places

Overlapping Congressional Districts

Congressional districtPopulation in bothShare of this district's populationShare of the congressional district's populationShare of this district's land
IL District 16150,61069.4%20.0%67.1%
IL District 1756,34926.0%7.5%28.7%
IL District 1110,1264.7%1.3%4.2%
IL District 146<0.1%<0.1%<0.1%

Source: U.S. Census Bureau 2020 blocks and 2025 block equivalency files (119th Congress, 2024 state legislative plans).

Voters

Registered Voters
158,297
Active Voters
147,144 (93.0%)

Party Registration

This state's voter file does not record party registration.

Turnout by Cycle

CycleGeneralDemocratic PrimaryRepublican Primary
2025–202632,311 (20.4%)134 (0.1%)<10 (—)
2023–2024112,227 (70.9%)7,921 (5.0%)18,282 (11.5%)
2021–202284,321 (53.3%)8,432 (5.3%)25,165 (15.9%)
2019–2020102,096 (64.5%)17,151 (10.8%)16,590 (10.5%)
2017–201876,023 (48.0%)10,904 (6.9%)21,546 (13.6%)
2015–201683,427 (52.7%)16,422 (10.4%)32,658 (20.6%)
2013–201456,955 (36.0%)3,837 (2.4%)19,317 (12.2%)
2011–201268,384 (43.2%)4,224 (2.7%)20,641 (13.0%)

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
215,911 (± 1,424)
Median Age
43.7
Median Household Income
$78,409 (± $1,794)
High School Graduate or Higher (age 25+)
92.7%
Bachelor's Degree or Higher (age 25+)
25.6%

Population by Age

GroupPeopleShare
Under 1847,16721.8%
18 to 64121,77156.4%
65 and over46,97321.8%

Population by Race and Hispanic Origin

GroupPeopleShare
Hispanic or Latino (any race)15,3117.1%
White, not Hispanic181,07783.9%
Black, not Hispanic6,5823.0%
Asian, not Hispanic2,2861.1%
American Indian / Alaska Native, not Hispanic2170.1%
Native Hawaiian / Pacific Islander, not Hispanic270.0%
Some other race, not Hispanic8170.4%
Two or more races, not Hispanic9,5944.4%

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
212,870
Citizen Voting Age Population (CVAP)
165,923

Citizen Population by Race/Ethnicity

GroupCitizensShare
Non-Hispanic199,25293.6%
Hispanic13,6206.4%
White183,56386.2%
Black6,6403.1%
Asian1,6620.8%
American Indian / Alaska Native2170.1%
Native Hawaiian / Pacific Islander240.0%
Two or More Races5540.3%

Citizen Voting Age Population by Race/Ethnicity

GroupCVAPShare
Non-Hispanic158,27395.4%
Hispanic7,6464.6%
White147,90989.1%
Black6,3243.8%
Asian1,6021.0%
American Indian / Alaska Native2,3021.4%
Native Hawaiian / Pacific Islander230.0%
Two or More Races1630.1%

Source: Redistricting Data Hub / U.S. Census Bureau CVAP Special Tabulation (2020-2024 ACS 5-year).