Adams County, Illinois
County seat: Quincy · Population 64,267 (2025) · 855 sq mi
Adams County is the 23rd most populous of Illinois's 102 counties, with 64,267 people (2025 estimate). Its county seat is Quincy. It is part of the West Central region, one of the 10 Illinois economic development regions (DCEO). The map shows its 14 cities and towns and the 6 neighboring counties.
Adams County facts
- County seat
- Quincy
- Population (2025 estimate)
- 64,267 −2.3% since 2020
- Land area
- 855 sq mi 12th largest of 102
- Water area
- 16 sq mi
- Population density
- 75 per sq mi
- Established
- 1825
- Same name
- One of 12 Adams Counties in the US
- Named after
- John Quincy Adams President of the United States from 1825 to 1829
- Largest city
- Quincy 38,918
- Median household income
- $66,220
- Cities and towns
- 14 plus 11 CDPs
- ZIP codes
- 23
- Time zone
- Central
- FIPS code
- 17001
Cities and towns in Adams County
Adams County has 14 incorporated cities, towns and villages. Populations count the people living inside Adams County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Quincy (county seat) | City | 38,918 | |
| Camp Point | Village | 1,119 | |
| Payson | Village | 994 | |
| Mendon | Village | 844 | |
| Golden | Village | 629 | |
| Clayton | Village | 616 | |
| Ursa | Village | 603 | |
| Liberty | Village | 522 | |
| Loraine | Village | 289 | |
| Plainville | Village | 260 | |
| Coatsburg | Village | 151 | |
| Lima | Village | 151 | |
| Columbus | Village | 110 | |
| La Prairie | Village | 40 |
Unincorporated communities (CDPs)
Census-designated places are communities without their own city government; the county provides their services.
| Community | Population | Also in |
|---|---|---|
| Paloma | 161 | |
| Burton | 149 | |
| Kingston | 132 | |
| Adams | 106 | |
| Marcelline | 33 | |
| Fowler | 32 | |
| Meyer | 22 | |
| Beverly | 0 | |
| Bloomfield | 0 | |
| Fall Creek | 0 | |
| Richfield | 0 |
ZIP codes in Adams County
23 ZIP codes reach into Adams County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 62301
- 62305
- 62311 also Hancock and Schuyler counties
- 62312 also Pike County
- 62314 also Pike County
- 62316 also Hancock County
- 62320
- 62324 also Brown County
- 62325
- 62338
- 62339
- 62343 also Pike County
- 62346 also Schuyler County
- 62347
- 62348
- 62349 also Hancock County
- 62351 also Hancock County
- 62359
- 62360
- 62365
- 62373 also Hancock County
- 62376
- 62379 also Hancock County
Population of Adams County, 2020–2025
Adams County shrank by 1,478 people (−2.3%) between April 2020 and July 2025: 649 more deaths than births and a net loss of 836 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 65,637 |
| 2021 | 65,149 |
| 2022 | 64,557 |
| 2023 | 64,508 |
| 2024 | 64,216 |
| 2025 | 64,267 |
Neighboring counties
- Hancock County north · 16,803 people
- Pike County southeast · 14,231 people
- Lewis County, Missouri west · 9,879 people
- Brown County east · 6,401 people
- Marion County, Missouri southwest · 28,525 people
- Schuyler County east · 6,657 people
Printable Adams 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) (94 KB)
- PNG (2400 px) (77 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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