Hancock County, Illinois
County seat: Carthage · Population 16,803 (2025) · 794 sq mi
Hancock County is the 61st most populous of Illinois's 102 counties, with 16,803 people (2025 estimate). Its county seat is Carthage. 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 7 neighboring counties.
Hancock County facts
- County seat
- Carthage
- Population (2025 estimate)
- 16,803 −4.8% since 2020
- Land area
- 794 sq mi 16th largest of 102
- Water area
- 21 sq mi
- Population density
- 21 per sq mi
- Established
- 1825
- Same name
- One of 10 Hancock Counties in the US
- Named after
- John Hancock American Patriot and statesman during the American Revolution (1737–1793)
- Largest city
- Hamilton 2,624
- Median household income
- $65,865
- Cities and towns
- 15 plus 1 CDPs
- ZIP codes
- 20
- Time zone
- Central
- FIPS code
- 17067
Cities and towns in Hancock County
Hancock County has 15 incorporated cities, towns and villages. Populations count the people living inside Hancock County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Hamilton | City | 2,624 | |
| Carthage (county seat) | City | 2,393 | |
| Warsaw | City | 1,436 | |
| La Harpe | City | 1,124 | |
| Nauvoo | City | 895 | |
| Dallas City | City | 613 | Henderson County |
| Augusta | Village | 531 | |
| Bowen | Village | 441 | |
| Plymouth | Village | 413 | McDonough County |
| Elvaston | Village | 141 | |
| West Point | Village | 136 | |
| Ferris | Village | 124 | |
| Pontoosuc | Village | 92 | |
| Basco | Village | 77 | |
| Bentley | Town | 26 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Niota | 39 |
ZIP codes in Hancock County
20 ZIP codes reach into Hancock County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 61420 also McDonough County
- 61450 also Henderson and McDonough counties
- 62311 also Schuyler and Adams counties
- 62313
- 62316 also Adams County
- 62321
- 62326 also McDonough County
- 62330 also Henderson County
- 62334
- 62336
- 62341
- 62349 also Adams County
- 62351 also Adams County
- 62354
- 62358
- 62367 also McDonough and Schuyler counties
- 62373 also Adams County
- 62374 also McDonough County
- 62379 also Adams County
- 62380
Population of Hancock County, 2020–2025
Hancock County shrank by 838 people (−4.8%) between April 2020 and July 2025: 404 more deaths than births and a net loss of 428 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 17,570 |
| 2021 | 17,412 |
| 2022 | 17,265 |
| 2023 | 17,192 |
| 2024 | 16,936 |
| 2025 | 16,803 |
Neighboring counties
- Adams County south · 64,267 people
- Lee County, Iowa northwest · 32,306 people
- McDonough County east · 25,916 people
- Henderson County northeast · 5,984 people
- Clark County, Missouri west · 6,475 people
- Schuyler County southeast · 6,657 people
- Lewis County, Missouri southwest · 9,879 people
Printable Hancock 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) (106 KB)
- PNG (2400 px) (86 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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