Marion County is a county in Iowa, United States, on the Des Moines River in the south-central part of the state. It had a population of 33,414 at the 2020 census and covers 571 square miles (1,479 km2), of which 555 square miles are land and 16 square miles are water, centred near 41°20′N 93°06′W.
Knoxville is the county seat, and its postal code is 50138. The county has nine incorporated cities, plus eight unincorporated communities and twelve civil townships. It sits in the Central time zone.
Towns & Villages in Marion County
Marion County has nine incorporated cities and eight recognized unincorporated communities. All nine incorporated places carry the legal designation “city” under Iowa law, regardless of size; Unincorp. marks a place with no municipal government of its own.
| Place | Type | Township | Pop. | ZIP |
|---|---|---|---|---|
| Knoxville | City · seat | Knoxville | 7,595 | 50138 |
| Pella | City | Lake Prairie | 10,464 | 50219 |
| Pleasantville | City | Pleasant Grove | 1,676 | 50225 |
| Melcher-Dallas | City | Dallas | 1,195 | 50163 |
| Bussey | City | Franklin | 387 | 50044 |
| Harvey | City | Liberty | 236 | 50119 |
| Hamilton | City | Summit | 119 | — |
| Swan | City | Union | 76 | 50252 |
| Marysville | City | Washington | 44 | — |
| Attica | Unincorp. | Indiana | — | — |
| Bauer | Unincorp. | Clay | — | — |
| Cloud | Unincorp. | — | — | — |
| Columbia | Unincorp. | — | — | — |
| Flagler | Unincorp. | — | — | — |
| Otley | Unincorp. | Clay | — | 50214 |
| Pershing | Unincorp. | Red Rock | — | — |
| Tracy | Unincorp. | Indiana | — | 50256 |
Knoxville is the county seat and largest inland city; Pella, on the county’s northeastern edge, is the county’s largest place overall.
Townships
Marion County has twelve civil townships. Population by township is not separately reported here; the table below lists each township and its principal settlement where one exists.
| Township | Pop. (2020) | Main settlements |
|---|---|---|
| Clay | — | Otley, Bauer |
| Dallas | — | Melcher-Dallas |
| Franklin | — | Bussey |
| Indiana | — | Attica, Tracy |
| Knoxville | — | Knoxville |
| Lake Prairie | — | Pella |
| Liberty | — | Harvey |
| Pleasant Grove | — | Pleasantville |
| Red Rock | — | Pershing |
| Summit | — | Hamilton |
| Union | — | Swan |
| Washington | — | Marysville |
ZIP Codes
- 50138 — Knoxville (also serves Pershing)
- 50219 — Pella
- 50225 — Pleasantville
- 50163 — Melcher-Dallas
- 50044 — Bussey
- 50119 — Harvey
- 50252 — Swan
- 50214 — Otley
- 50256 — Tracy
Hamilton and Marysville do not have their own post offices and are served by nearby ZIP codes not confirmed here.
Geography
Marion County lies on the Des Moines River, which the Red Rock Dam impounds into Lake Red Rock, Iowa’s largest lake by surface area, just east of Pella. Elk Rock State Park sits on the lake’s north shore. The county is rolling farmland typical of south-central Iowa, drained by the Des Moines River and several smaller creeks that feed it.
Marion County borders Jasper County to the north, Mahaska County to the east, Monroe County to the southeast, Lucas County to the southwest, and Warren County to the west. Monroe County’s page is live at townsvillages.com/us/monroe-county-iowa/; Mahaska County is Iowa’s Mahaska County, not to be confused with any other state’s county of the same name.
Demographics
Marion County had 33,414 residents at the 2020 census, spread across a land area of 555 square miles for a density of about 60 people per square mile. Pella (10,464) and Knoxville (7,595) are the county’s two largest communities and together hold more than half the county’s population. Median household income in the county runs close to the Iowa median of $71,433, reflecting the mix of manufacturing jobs in Pella and Knoxville with the county’s farm economy.
Economy & Local Life
Pella is home to Pella Corporation, the window and door manufacturer founded there in 1925, and to Vermeer Corporation, a manufacturer of agricultural and industrial equipment headquartered just outside the city — both are major regional employers. Knoxville hosts Knoxville Raceway, a dirt-track speedway that stages the Knoxville Nationals sprint car race each August and draws visitors from across the country. Pella’s Dutch heritage is marked every May with Tulip Time, a multi-day festival with parades and traditional dress. Away from the two main cities, farming remains the primary land use across the county.
History
Marion County was organized in 1845 and named for Francis Marion, the South Carolina militia general nicknamed the “Swamp Fox” during the American Revolutionary War. Dutch immigrants led by Hendrik Pieter Scholte founded Pella in 1847, and the settlement kept much of its Dutch character into the 20th century. The Red Rock Dam, completed by the U.S. Army Corps of Engineers in 1969, flooded farmland along the Des Moines River to create Lake Red Rock and reshaped the county’s northeastern geography.
Getting There
U.S. Route 65 runs north-south through the county’s east side, and Iowa Highway 14 crosses through Pella and Knoxville. Nearby cities:
- Des Moines — 40 miles northwest
- Oskaloosa — 20 miles east
- Newton — 25 miles north
- Ottumwa — 35 miles southeast
Des Moines International Airport, about 45 miles northwest, is the nearest commercial airport.
Frequently Asked Questions
Where is Marion County, Iowa?
It sits in Iowa’s south-central section, on the Des Moines River, about 40 miles southeast of Des Moines.
What is the population of Marion County?
33,414 people, per the 2020 census.
How big is Marion County?
571 square miles, including 16 square miles of water — most of it Lake Red Rock.
What is the county seat of Marion County?
Knoxville is the county seat.
How many towns are in Marion County?
Nine incorporated cities and eight unincorporated communities.
What ZIP codes are in Marion County?
Including 50138 (Knoxville), 50219 (Pella), 50225 (Pleasantville), 50163 (Melcher-Dallas), 50044 (Bussey), 50119 (Harvey), and 50252 (Swan).
What is Marion County known for?
Pella’s Dutch-founded downtown and its Tulip Time festival, Knoxville Raceway’s sprint car racing, and Lake Red Rock, Iowa’s largest lake by surface area.
More counties in this state: Towns and villages in Iowa.