Putnam County, Illinois
County seat: Hennepin · Population 5,619 (2025) · 160 sq mi
Putnam County is the 94th most populous of Illinois's 102 counties, with 5,619 people (2025 estimate). Its county seat is Hennepin. It is part of the Northwest region, one of the 10 Illinois economic development regions (DCEO). The map shows its 6 cities and towns and the 3 neighboring counties.
Putnam County facts
- County seat
- Hennepin
- Population (2025 estimate)
- 5,619 −0.2% since 2020
- Land area
- 160 sq mi 102nd largest of 102
- Water area
- 12 sq mi
- Population density
- 35 per sq mi
- Established
- 1825
- Same name
- One of 9 Putnam Counties in the US
- Named after
- Israel Putnam American Revolutionary War general (1718–1790)
- Largest city
- Granville 1,325
- Median household income
- $75,590
- Cities and towns
- 6
- ZIP codes
- 8
- Time zone
- Central
- FIPS code
- 17155
Cities and towns in Putnam County
Putnam County has 6 incorporated cities, towns and villages. Populations count the people living inside Putnam County; cities that cross a county line also list the other counties.
| Name | Type | Population 2025 | Also in |
|---|---|---|---|
| Granville | Village | 1,325 | |
| Hennepin (county seat) | Village | 747 | |
| Mark | Village | 505 | |
| McNabb | Village | 273 | |
| Magnolia | Village | 256 | |
| Standard | Village | 221 |
ZIP codes in Putnam County
8 ZIP codes reach into Putnam County. ZIP codes ignore county lines, so some also cover a neighboring county.
- 61326
- 61327
- 61334 also LaSalle County
- 61335
- 61336 also Marshall County
- 61340
- 61363
- 61560 also Marshall and Bureau counties
Population of Putnam County, 2020–2025
Putnam County shrank by 12 people (−0.2%) between April 2020 and July 2025: 58 more deaths than births and a net gain of 49 people from migration.
| Year (July 1) | Population |
|---|---|
| 2020 | 5,624 |
| 2021 | 5,585 |
| 2022 | 5,559 |
| 2023 | 5,580 |
| 2024 | 5,617 |
| 2025 | 5,619 |
Neighboring counties
- Bureau County northwest · 32,510 people
- Marshall County south · 11,473 people
- LaSalle County northeast · 107,773 people
Printable Putnam 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) (67 KB)
- PNG (2400 px) (55 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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