Adams County is a county in Indiana, United States, on the state’s eastern border with Ohio. It had a population of 35,809 at the 2020 census and covers 339.97 square miles (880.5 km2) centred near 40°45′N 84°56′W.
Decatur is the county seat, and its postal code is 46733. The county holds four incorporated cities and towns — Berne, Decatur, Geneva and Monroe — plus more than a dozen unincorporated communities, all organised into 12 civil townships. Adams County is in the Eastern time zone and carries FIPS code 18001.
Towns & Villages in Adams County
Adams County has four incorporated places and about a dozen unincorporated communities and crossroads settlements. “City · seat” marks the county seat; “Unincorp.” marks a community with no municipal government of its own.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Decatur | City · seat | — | — | 46733 |
| Berne | City | — | — | 46711 |
| Geneva | Town | — | — | 46740 |
| Monroe | Town | — | — | 46772 |
| Ceylon | Unincorp. | — | — | — |
| Coppess Corner | Unincorp. | — | — | — |
| Elm Tree Crossroads | Unincorp. | — | — | — |
| Honduras | Unincorp. | — | — | — |
| Linn Grove | Unincorp. | — | — | — |
| Magley | Unincorp. | — | — | — |
| Monmouth | Unincorp. | — | — | — |
| Perryville | Unincorp. | — | — | — |
| Peterson | Unincorp. | — | — | — |
| Pleasant Mills | Unincorp. | — | — | — |
| Preble | Unincorp. | — | — | — |
| Salem | Unincorp. | — | — | — |
| Williams | Unincorp. | — | — | — |
The old listing’s “Rivare” entry does not correspond to any place name on record for Adams County and has been dropped as an apparent scrape error — it is not carried into the table above.
Townships
Adams County is divided into 12 civil townships: Blue Creek, French, Hartford, Jefferson, Kirkland, Monroe, Preble, Root, St. Marys, Union, Wabash and Washington. Township-level 2020 census population figures and settlement-to-township assignments were not confirmed within this rewrite’s sourcing and are omitted rather than guessed.
ZIP Codes
- 46733 — Decatur (county seat)
- 46711 — Berne
- 46740 — Geneva
- 46772 — Monroe
The county’s smaller unincorporated communities are served by the ZIP code of the nearest post-office town rather than one of their own.
Geography
Adams County sits on flat to gently rolling farmland typical of northeastern Indiana’s till plain, drained by the St. Marys River and the headwaters of the Wabash River system. Most of the county’s land is in row-crop agriculture, with woodlots and wetland remnants along the river corridors.
Adams County borders Allen County to the north, Van Wert County, Ohio to the east, Mercer County, Ohio to the southeast, Jay County to the south, and Wells County to the west.
Demographics
Adams County’s population was 35,809 at the 2020 census, a density of about 108 people per square mile. Decatur and Berne are the county’s two largest communities. An estimated quarter of the county’s population is Swiss Amish, concentrated in and around Berne in the southern half of the county. Median household income in the county runs below the Indiana median of $69,477, reflecting the county’s largely agricultural economy.
Economy & Local Life
Agriculture — corn, soybeans and livestock — anchors the county’s economy, alongside manufacturing and food-processing employers based in Decatur and Berne. Berne’s Swiss Mennonite heritage shapes much of the county’s local life, most visibly at the town’s annual Swiss Days festival, which draws visitors for Swiss-style food, crafts and music.
History
Adams County was organised on March 1, 1836, and named for President John Quincy Adams. Berne was settled in the 1850s by Swiss Mennonite immigrants, whose descendants’ Swiss heritage remains a defining feature of the county’s southern townships.
Getting There
Three U.S. routes cross the county — US 27, US 33 and US 224 — along with state roads 101, 116, 124 and 218. A CSX rail line runs from Decatur north to Fort Wayne.
- Fort Wayne — about 24 miles north via US 27
- Van Wert, Ohio — about 20 miles east via US 224
- Muncie — about 45 miles south via US 27/SR 1
- Bluffton (Wells County) — about 15 miles west via SR 116
The nearest commercial airport is Fort Wayne International Airport, roughly 30 miles to the north.
Frequently Asked Questions
Where is Adams County, Indiana?
It is in northeastern Indiana on the Ohio state line, roughly 25 miles south of Fort Wayne.
What is the population of Adams County?
35,809 at the 2020 census.
How big is Adams County?
339.97 square miles (880.5 km2), of which 339.03 square miles is land.
What is the Adams County seat?
Decatur is the county seat.
How many towns are in Adams County?
Four incorporated cities and towns — Berne, Decatur, Geneva and Monroe — plus more than a dozen unincorporated communities.
What ZIP codes are in Adams County?
Decatur is 46733; Berne is 46711; Geneva is 46740; and Monroe is 46772.
What is Adams County known for?
Its Swiss Mennonite heritage, centred on Berne, including the town’s annual Swiss Days festival.
More counties in this state: Towns and villages in Indiana.