Johnson County is a county in Indiana, United States, just south of Indianapolis in the north-central part of the state. It had a population of 161,765 at the 2020 census and covers 321.79 square miles (833.4 km2), of which 320.43 square miles is land and 1.36 square miles is water, centred near 39°29′N 86°06′W.
Franklin is the county seat, and its postal code is 46131. The county has two cities, six towns, and more than a dozen smaller unincorporated communities, spread across seven civil townships. Johnson County sits in the Eastern time zone and is part of the Indianapolis metropolitan area.
Towns & Villages in Johnson County
Johnson County has 21 named places worth noting: 2 cities, 6 incorporated towns, and 13 unincorporated communities or crossroads. CDP denotes a Census-designated place with no city government; Unincorp. denotes a rural community with no incorporated boundary.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Franklin | City · seat | Franklin-Union-Needham | 25,313 | 46131 |
| Greenwood | City | White River | 63,830 | 46142–46143 |
| Bargersville | Town | White River / Union | 9,560 | 46106 |
| Edinburgh | Town | — | — | — |
| New Whiteland | Town | Pleasant | — | — |
| Princes Lakes | Town | Hensley | — | — |
| Trafalgar | Town | Blue River | — | — |
| Whiteland | Town | Pleasant | — | — |
| Amity | Unincorp. | Clark | — | — |
| Bluff Creek | Unincorp. | — | — | — |
| Hopewell | Unincorp. | — | — | — |
| McCarty | Unincorp. | — | — | — |
| Mount Pleasant | Unincorp. | — | — | — |
| Needham | Unincorp. | Franklin-Union-Needham | — | — |
| Nineveh | Unincorp. | Nineveh | — | — |
| Peoga | Unincorp. | — | — | — |
| Providence | Unincorp. | — | — | — |
| Rocklane | Unincorp. | — | — | — |
| Samaria | Unincorp. | Nineveh | — | — |
| Smith Valley | Unincorp. | — | — | — |
| Waterloo | Unincorp. | — | — | — |
Edinburgh straddles the Johnson–Shelby–Bartholomew county line, with most of the town’s built-up area on the Johnson County side; its post office and municipal address book cover residents in all three counties. Whiteland and New Whiteland are adjoining but separately incorporated towns along US 31, and are easy to mix up on a map.
Townships
Johnson County has seven civil townships. Franklin, Union, and Needham townships consolidated into a single Franklin-Union-Needham Township in January 2022, reducing the county from nine townships to seven.
| Township | Pop. (2020) | Main settlements |
|---|---|---|
| White River | — | Greenwood, Bargersville (part) |
| Franklin-Union-Needham | — | Franklin, Needham |
| Pleasant | — | Whiteland, New Whiteland |
| Clark | — | Amity |
| Blue River | — | Trafalgar |
| Nineveh | — | Nineveh, Samaria |
| Hensley | — | Princes Lakes |
ZIP Codes
- 46131 — Franklin (post office town)
- 46142–46143 — Greenwood (also serves White River and part of Pleasant Township)
- 46106 — Bargersville (also serves White River and Union areas)
The county’s smaller towns and unincorporated communities share ZIP codes with the nearest post office town rather than carrying their own; residents of Edinburgh, New Whiteland, Princes Lakes, Trafalgar, and Whiteland should check the current carrier route rather than assume a single county-wide code.
Geography
Johnson County lies on the till plains of central Indiana, mostly flat to gently rolling, with the terrain growing hillier toward Brown County to the southwest. The White River’s Driftwood and West Fork branches touch the county’s western and northern edges, and Sugar Creek and Blue River drain the southern townships.
Johnson County borders Marion County to the north, Shelby County to the east, Bartholomew County to the southeast, Brown County to the southwest, and Morgan County to the west.
Demographics
Johnson County counted 161,765 residents in the 2020 census. Greenwood, its largest city at 63,830 people, and Franklin, the county seat at 25,313, together hold more than half the county’s population. Household income runs well above the Indiana median of $69,477, reflecting the county’s role as a commuter suburb of Indianapolis. Population density works out to roughly 505 people per square mile of land.
Economy & Local Life
Johnson County’s economy centers on retail, logistics, and healthcare tied to the Indianapolis metro, along with manufacturing around Franklin and Whiteland. Franklin College, a private liberal-arts college founded in 1834, anchors the county seat. Johnson Memorial Health operates the county’s main hospital in Franklin. The Johnson County Fair, held each July in Franklin, remains the county’s largest annual community event.
History
Johnson County was organized in 1823 and named for John Johnson, a justice of the Indiana Supreme Court. Franklin was platted as the county seat the same year. The county grew as a farming and rail-shipping district through the 19th century before its northern townships were absorbed into the Indianapolis suburban belt in the second half of the 20th century, driving most of the county’s modern population growth.
Getting There
Interstate 65 crosses the county’s east side through Whiteland and Edinburgh, and Interstate 69 runs along the western edge; U.S. Route 31 and State Roads 44, 135, 144, and 252 cover the rest of the county.
- Indianapolis — 20 miles north
- Bloomington — 35 miles southwest
- Columbus, Indiana — 25 miles southeast
- Nashville, Indiana — 20 miles south
Indianapolis International Airport, about 25 miles northwest of Franklin, is the nearest commercial airport. Greenwood Municipal Airport and Franklin Flying Field serve general aviation.
Frequently Asked Questions
Where is Johnson County, Indiana?
It sits just south of Indianapolis in the north-central part of the state, bordered by Marion, Shelby, Bartholomew, Brown, and Morgan counties.
What is the population of Johnson County?
161,765 people, according to the 2020 census.
How big is Johnson County?
321.79 square miles (833.4 km2), of which 320.43 square miles is land.
What is the county seat of Johnson County?
Franklin is the county seat.
How many towns are in Johnson County?
Two cities (Franklin and Greenwood) and six incorporated towns, plus more than a dozen unincorporated communities.
What ZIP codes are in Johnson County?
Franklin uses 46131, Greenwood uses 46142–46143, and Bargersville uses 46106; other towns share ZIP codes with the nearest post office.
What college is in Johnson County?
Franklin College, a private liberal-arts college founded in 1834, is based in Franklin.
More counties in this state: Towns and villages in Indiana.