Illinois population
State · Official geographic code 17
· Annual resident population estimate
U.S. Census Bureau · Population Estimates Program · Vintage 2025
+16,108 residents (+0.13%) since July 1, 2024.
- Population change, 2020–2025
- -76,207July 1 to July 1 · -0.60%
- Land-area density, 2025
- 229.1People per square mile · 2025 land area
- Population rank, 2025
- 6 of 5050 states; DC listed separately
Illinois population history
Open historical explorerThese six July 1 estimates belong to one consistent Vintage 2025 series. The Census Bureau revises earlier years when it releases a new vintage; a figure from an older publication may differ from the value below.
Annual estimates · 2020–2025 · Vertical scale shown on chart.
The highest observed population in this annual series was 12,795,348 in 2020. This is a peak within 2020–2025 coverage, not an all-time record.
| Reference date | Population | Annual change |
|---|---|---|
| July 1, 2020 | 12,795,348 | — |
| July 1, 2021 | 12,703,354 | -91,994 |
| July 1, 2022 | 12,609,577 | -93,777 |
| July 1, 2023 | 12,633,389 | +23,812 |
| July 1, 2024 | 12,703,033 | +69,644 |
| July 1, 2025 | 12,719,141 | +16,108 |
Why is the April 2020 estimates base different from a census count?
The PEP estimates base here is 12,821,741 residents on April 1, 2020. It incorporates the Census Bureau’s corrections and geographic revisions and serves as the starting point for this annual series. It is not labeled an original 2020 census count. The chart starts at July 1, 2020, so its five-year change uses two July observations. Read about measurement types.
Decennial census counts, 1910–2020
These are separate census observations from the Census Bureau’s historical population-change table. Historical geographic definitions apply; they are not standardized to the 2025 boundary. Alaska and Hawaii were not states throughout this period. Census dates changed historically: April 15, 1910; January 1, 1920; April 1, 1930 and 1940; and April 1 from 1950 onward. The national historical source must be read with its coverage notes.
| Census year | Resident population | Measurement |
|---|---|---|
| 1910 | 5,638,591 | Census count |
| 1920 | 6,485,280 | Census count |
| 1930 | 7,630,654 | Census count |
| 1940 | 7,897,241 | Census count |
| 1950 | 8,712,176 | Census count |
| 1960 | 10,081,158 | Census count |
| 1970 | 11,113,976 | Census count |
| 1980 | 11,426,518 | Census count |
| 1990 | 11,430,602 | Census count |
| 2000 | 12,419,293 | Census count |
| 2010 | 12,830,632 | Census count |
| 2020 | 12,812,508 | Census count |
Growth and density
Between July 1, 2020 and July 1, 2025, Illinois lost 76,207 residents, a 0.60% decrease. The annualized change over these five elapsed years was -0.12%. Annualized change is a summary of the interval; it does not imply that the population changed at that rate in every year.
The 2025 Gazetteer reports 55,513.52 square miles of land. Dividing the July 1, 2025 population by that compatible land area gives 229.1 people per square mile. Water area is excluded. Density depends on geographic boundaries. It describes this entire geography, rather than a typical neighborhood or built-up area.
Calculations use unrounded source values. Population counts are displayed as integers, percentages to two decimals and density to one decimal. Calculation methods · Growth calculator
Components of population change
The published components cover July 1, 2024 through June 30, 2025. Natural change equals births minus deaths. Net migration is arrivals minus departures; it does not establish why people moved.
| Component | People |
|---|---|
| Births | 125,129 |
| Deaths | 114,226 |
| Natural change | +10,903 |
| Net domestic migration | -40,017 |
| Net international migration | +44,752 |
| Residual | +470 |
| Total population change | +16,108 |
Reconciliation: natural change + net domestic migration + net international migration + residual = +16,108. Births and deaths are already included in natural change and must not be added again. Source: NST-EST2025-ALLDATA.csv; Vintage 2025.
Age structure, race and Hispanic-origin panels are not included in this totals release. Their separate periods, definitions and uncertainty will be validated before publication. Coverage details.
Geographic context
County totals below describe separate county units. Incorporated cities are not an exhaustive division of a state, so their populations must not be summed as a state control total.
| Place | Population · 2025 | Change · 2024–25 | Growth · 2024–25 | People / sq. mi. |
|---|---|---|---|---|
| Cook CountyIllinois · County equivalent · 17031 | 5,194,625 | +5,834 | +0.11% | 5,497.4 |
| DuPage CountyIllinois · County equivalent · 17043 | 934,298 | +1,647 | +0.18% | 2,849.4 |
| Lake CountyIllinois · County equivalent · 17097 | 719,339 | +849 | +0.12% | 1,621.3 |
| Will CountyIllinois · County equivalent · 17197 | 712,253 | +3,273 | +0.46% | 852.1 |
| Kane CountyIllinois · County equivalent · 17089 | 525,757 | +2,327 | +0.44% | 1,012.3 |
| McHenry CountyIllinois · County equivalent · 17111 | 317,751 | +2,021 | +0.64% | 526.6 |
| Winnebago CountyIllinois · County equivalent · 17201 | 283,674 | +709 | +0.25% | 552.9 |
| Madison CountyIllinois · County equivalent · 17119 | 263,110 | -207 | -0.08% | 367.7 |
| St. Clair CountyIllinois · County equivalent · 17163 | 250,708 | -667 | -0.27% | 381.2 |
| Champaign CountyIllinois · County equivalent · 17019 | 209,972 | +794 | +0.38% | 210.8 |
Showing 10 of 102 related records. All counties · All incorporated places
Places with nearby population ranks
Selected from the same 2025 comparison universe, using neighboring population ranks. Similar population does not imply similar density, boundaries or demographics.
| Place | Population · 2025 | Change · 2024–25 | Growth · 2024–25 | People / sq. mi. |
|---|---|---|---|---|
| New YorkNew York · State · 36 | 20,002,427 | +1,008 | +0.01% | 424.5 |
| PennsylvaniaPennsylvania · State · 42 | 13,059,432 | +13,584 | +0.10% | 291.9 |
| OhioOhio · State · 39 | 11,900,510 | +39,889 | +0.34% | 291.3 |
| GeorgiaGeorgia · State · 13 | 11,302,748 | +98,540 | +0.88% | 195.8 |
Source, citation and downloads
U.S. Census Bureau, Population Estimates Program, Vintage 2025, NST-EST2025-ALLDATA.csv, variable POPESTIMATE2025; Illinois, Illinois, geographic code 17; resident population 12,719,141 on July 1, 2025; boundaries January 1, 2025. https://www2.census.gov/programs-surveys/popest/datasets/2020-2025/state/totals/NST-EST2025-ALLDATA.csv. Retrieved September 30, 2026. US Population Data snapshot pep-2025-r1, transformation 1.
Inspect this observation
Full datasets and dictionary · Release notes and checksums · Report a correction