County · code 19125
Marion CountyIowa
Marion County is a county in Iowa, with its seat in Knoxville, formed in 1845.
- Founded1845
- County seatKnoxville
- Named forFrancis Marion
- Land area554 sq mi + 16 sq mi water
- Population33,414 2020 Census
- Parcels mapped15,753 checked 15 October 2026
Where it is
Marion on the map of Iowa
Iowa has 99 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1845 from Mahaska County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Marion County was formed in 1845 from Mahaska County, and named after Francis Marion. Knoxville is the county seat.
Deeds and plats from before 1845 for land now in Marion County may have been recorded in Mahaska County.
- 1845Marion County created Marion created by Iowa Territory from Non-County Area 3 attached to Mahaska. · Iowa Terr. Laws 1845, ch. 57, sec. 1/pp. 93-96
- 1846Became part of Iowa Marion became an Iowa county when the state of Iowa was created from Iowa Territory. · U.S. Stat., vol. 9, ch. 1[1847]/p. 117
- 1847Boundary clarified Marion's boundaries redefined (no change).no change· Iowa Acts 1846-1847, ch. 15, secs. 1, 3/p. 36
Land and parcels
What the maps cover in Marion
Who publishes each layer, how good it is, and when we last checked.
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Parcels Good enough
Lot lines and tax-map numbers for 15,753 parcels from Marion County. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 15 October 2026 -
Address points Missing
No public address points layer found for Marion County yet.
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Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
Marion by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
Rules and offices
Who to ask before you build, dig or sell
Official county pages only. We link to them; we do not copy them, because they change.
Inside a city or town, permits usually come from that city rather than the county.
Records
Zoning and code
GIS and maps
County government
- County government
The official website of Marion County.
See your own lot on these maps
Open Marion County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Marion County
- When was Marion County founded?
- Marion County was founded in 1845, formed from Mahaska County, and named after Francis Marion.
- What is the county seat of Marion County?
- The county seat of Marion County is Knoxville.
- Is there an online parcel map for Marion County?
- Yes. Marion County publishes a parcel map of 15,753 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Marion County's boundary or name changed?
- Marion County was created in 1845 from Mahaska County. Since then the Atlas of Historical County Boundaries records 1 later change.
- Who issues building permits in Marion County?
- The county's page on building permits: Building Permits - Marion County, Iowa. Inside a city or town, ask that city first.
- Is my lot in a flood zone?
- We do not have flood maps for Marion County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby