Knox County, Illinois
County seat: Galesburg · Population 47,767 (2025) · 716 sq mi
Knox County is the 30th most populous of Illinois's 102 counties, with 47,767 people (2025 estimate). Its county seat is Galesburg. It is part of the West Central region, one of the 10 Illinois economic development regions (DCEO). The map shows its 15 cities and towns and the 6 neighboring counties.
Knox County facts
- County seat
- Galesburg
- Population (2025 estimate)
- 47,767 −4.4% since 2020
- Land area
- 716 sq mi 21st largest of 102
- Water area
- 3 sq mi
- Population density
- 67 per sq mi
- Established
- 1825
- Same name
- One of 9 Knox Counties in the US
- Named after
- Henry Knox American general and Secretary of War (1750–1806)
- Largest city
- Galesburg 28,581
- Median household income
- $57,030
- Cities and towns
- 15 plus 2 CDPs
- ZIP codes
- 23
- Time zone
- Central
- FIPS code
- 17095
Cities and towns in Knox County
Knox County has 15 incorporated cities, towns and villages. Populations count the people living inside Knox County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Galesburg (county seat) | City | 28,581 | |
| Abingdon | City | 2,832 | |
| Knoxville | City | 2,810 | |
| East Galesburg | Village | 734 | |
| Wataga | Village | 712 | |
| Oneida | City | 677 | |
| Yates City | Village | 629 | |
| Williamsfield | Village | 550 | |
| Altona | Village | 449 | |
| Henderson | Village | 254 | |
| Victoria | Village | 252 | |
| Maquon | Village | 211 | |
| Rio | Village | 203 | |
| St. Augustine | Village | 113 | |
| London Mills | Village | 4 | Fulton County |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Oak Run | 800 | |
| Gilson | 120 |
ZIP codes in Knox County
23 ZIP codes reach into Knox County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 61401 also Warren County
- 61402
- 61410 also Warren County
- 61414 also Henry County
- 61428
- 61430
- 61434 also Henry and Stark counties
- 61436
- 61439
- 61448
- 61449 also Stark County
- 61458
- 61467
- 61472 also Mercer County
- 61474 also Warren and Fulton counties
- 61485
- 61488
- 61489 also Peoria County
- 61490 also Henry County
- 61529 also Peoria County
- 61531 also Fulton and Peoria counties
- 61544 also Fulton County
- 61572
Population of Knox County, 2020–2025
Knox County shrank by 2,209 people (−4.4%) between April 2020 and July 2025: 1,324 more deaths than births and a net loss of 913 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 49,812 |
| 2021 | 49,306 |
| 2022 | 48,662 |
| 2023 | 48,191 |
| 2024 | 47,964 |
| 2025 | 47,767 |
Neighboring counties
- Warren County west · 16,222 people
- Fulton County south · 32,901 people
- Henry County north · 48,095 people
- Peoria County southeast · 178,553 people
- Stark County northeast · 5,319 people
- Mercer County northwest · 15,229 people
Printable Knox County map
The PDF is a vector file with real text: it prints sharp on Letter paper and you can search it for a town. The PNG is 2400 pixels wide for slides and documents. Both are free to use with a credit to WhichCounty.
- PDF (Letter) (99 KB)
- PNG (2400 px) (76 KB)
Paste this code to embed the map on your site:
Sources
- Boundaries: U.S. Census Bureau, 2025 Cartographic Boundary Files (1:500,000).
- Population: Census Bureau county and city estimates, Vintage 2025. CDP populations: American Community Survey 2020–2024.
- Places and ZIP codes: Census Bureau 2026 Gazetteer and 2020 ZIP Code Tabulation Area relationship files.
- County seat, founding year and name origin: Wikidata (CC0), checked against state sources.
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