When was Marion County founded?

Marion County was founded in 1843, formed from Champoeg County and Champooick County, and named after Francis Marion.

What is the county seat of Marion County?

The county seat of Marion County is Salem.

Is there an online parcel map for Marion County?

Yes. Marion County publishes a parcel map of 115,870 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 1843 from Champoeg County and Champooick County. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Linn County, Champoeg County and Champoeg District. It was formerly called Champoeg District and Champoeg.

Who issues building permits in Marion County?

The county's page on building permits: MCPWTranspPermits@co.marion.or.us. Inside a city or town, ask that city first.

Who issues septic and well permits in Marion County?

The county's page on septic systems and wells: Health Services.

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.

County · code 41047

Marion CountyOregon

Marion County is in Oregon and has its seat in Salem. It was created on July 5, 1843, as Champoeg District, one of four original counties of the Oregon Territory.

Founded1843
County seatSalem
Named forFrancis Marion
Land area1,181 sq mi + 10 sq mi water
Population345,920 2020 Census
Parcels mapped115,870 checked 14 October 2026

Open the free map Click any parcel in Marion County: acreage, parcel id, address and who publishes the map. No sign-in.

Updated 20 October 2026

Census outline · seat marked

History

Formed in 1843 from Champoeg County and Champooick County

An old deed may name a county that no longer exists, or a boundary that has since moved.

Champoeg District was formed as one of four original districts created by the Provisional Legislature of Oregon Territory, originally including parts of present-day Oregon, Washington, Idaho, and Montana. The district lost land to Clackamas County in 1845 and to the newly created Linn County in 1847, while its boundaries were redefined relative to Yamhill District. Champoeg District was renamed Champoeg County in 1845 and then renamed Marion in 1849, after Francis Marion. Marion became an Oregon county when the state was admitted to the Union in 1859 and Oregon Territory was eliminated.

Boundary changes from the Newberry Library, Atlas of Historical County Boundaries; the 5 that matter most are shown first.

1843
Marion County created Champoeg District (now Marion) created. Champoeg was one of four original counties created by the Provisional Legislature of Oregon Territory. Included parts of present Oregon, Washington, Idaho, and Montana. Name was also spelled Champooick.
from Champoegfrom Champooick
5 July 1843 · Oregon Archives, p. 26
1845
Lost territory Champoeg District (now Marion) lost to Clackamas District. Boundary between Champoeg District and Yamhill District redefined to run "along the middle of the main channel of the Willamette River to the center of the Columbia River at the upper mouth of the Willamette."
to Clackamas Districtto Yamhill District
19 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, pp. 35-37
1845
Renamed Champoeg District (now Marion) renamed Champoeg County; no change in boundaries.
formerly Champoeg District
22 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, p.35
1849
Renamed Champoeg renamed Marion.
formerly Champoeg
3 September 1849 · Ore. Terr. Laws 1850, 2nd sess., p. 53
1859
Became part of Oregon Marion became an Oregon county when the state of Oregon was admitted to the Union and Oregon Territory was eliminated. 14 February 1859 · U.S. Stat., vol. 11, ch. 33[1859], secs. 1-2/pp. 383-384 Ore. Laws 1860, 1st reg. sess., pp. 28-30

Show all 13 changes (8 more)

1843
Marion County created Champoeg District (now Marion) created. Champoeg was one of four original counties created by the Provisional Legislature of Oregon Territory. Included parts of present Oregon, Washington, Idaho, and Montana. Name was also spelled Champooick.
from Champoegfrom Champooick
5 July 1843 · Oregon Archives, p. 26
1845
Lost territory Champoeg District (now Marion) lost to Clackamas District. Boundary between Champoeg District and Yamhill District redefined to run "along the middle of the main channel of the Willamette River to the center of the Columbia River at the upper mouth of the Willamette."
to Clackamas Districtto Yamhill District
19 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, pp. 35-37
1845
Renamed Champoeg District (now Marion) renamed Champoeg County; no change in boundaries.
formerly Champoeg District
22 December 1845 · Ore. Terr. Laws, general and local, 1843-1849, p.35
1847
Lost territory Champoeg (now Marion) lost to creation of Linn.
to Linn
28 December 1847 · Ore. Terr. Laws, general and local, 1843-1849, pp. 55-56
1849
Renamed Champoeg renamed Marion.
formerly Champoeg
3 September 1849 · Ore. Terr. Laws 1850, 2nd sess., p. 53
1854
Lost territory Marion lost to creation of Wasco.
to Wasco
11 January 1854 · Ore. Terr. Special Laws 1853, 5th reg. sess., pp. 26-27
1856
Lost territory Marion lost to Clackamas.
to Clackamas
30 January 1856 · Ore. Terr. Laws 1855-1856, 7th reg. sess., p. 50
1859
Became part of Oregon Marion became an Oregon county when the state of Oregon was admitted to the Union and Oregon Territory was eliminated. 14 February 1859 · U.S. Stat., vol. 11, ch. 33[1859], secs. 1-2/pp. 383-384 Ore. Laws 1860, 1st reg. sess., pp. 28-30
1911
Boundary clarified Marion boundary with Clackamas redefined (no change).
with Clackamasno change
8 February 1911 · Ore. Laws 1911, gen., 26th reg. sess., ch. 22/p. 39
1913
Lost territory Marion lost to Linn.
to Linn
25 February 1913 · Ore. Laws 1913, gen., 27th reg. sess., ch. 109/p. 184
1981
Boundary clarified Marion boundary with Yamhill redefined to run along middle of the main channel of the Willamette River as it was located on 22 June 1981 (no change).
with Yamhillno change
22 June 1981 · Ore. Laws 1981, 61st reg. sess., ch. 214/p. 225
1983
Boundary clarified Marion boundary with Polk redefined to run along main channel of Willamette River as it was located on 22 June 1981 (no change).
with Polkno change
5 August 1983 · Ore. Laws 1983, 62nd reg. sess., ch. 780/pp. 1516-1517
1985
Boundary clarified Marion boundary with Linn redefined to run along the middle of the main channel of the Santiam River, and along the middle of the main channel of the north fork of the Santiam River as they existed on 21 April 1982 (no change).
with Linnno change
23 May 1985 · Ore. Laws 1985, 63rd reg. sess., ch. 122/p. 407

Land and parcels

What the maps cover in Marion

Who publishes each layer, how good it is, and when we last checked.

Parcels Good enough

Lot lines and tax-map numbers for 115,870 parcels from Marion County. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 14 October 2026
Address points Official

One point per address, 162,956 in all from State of Oregon — Department of Administrative Services Geospatial Enterprise Office (GEOHub) with Oregon Department of Emergency Management 9-1-1 program.
edited 16 January 2026 · checked 13 October 2026
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

Population

345,920 2020 Census count

Housing units

128,541 2020 Census count

Land area

1,181 square miles

Water area

10 square miles

People per sq mi

293 population ÷ land area

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.

Permits

Health department: septic and well
Health Services
from co.marion.or.us · checked 13 October 2026
MCPWTranspPermits@co.marion.or.usfrom co.marion.or.us
Annual Blanket Permit GISfrom co.marion.or.us
EPA - About Private Water Wellsfrom co.marion.or.us
Licensed Septic System Installers & Pumpersfrom co.marion.or.us

Zoning and code

Planning and zoning
Contact Planning Staff
from co.marion.or.us · checked 13 October 2026
County Codes & Ordinancesfrom codepublishing.com
Land Use Planning and Zoning Mapsfrom co.marion.or.us
Zoning Mapsfrom co.marion.or.us

County government

County government
The official website of Marion County.
co.marion.or.us

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.

Open the free map no sign-in Pro early access

Questions

Common questions about Marion County

When was Marion County founded?: Marion County was founded in 1843, formed from Champoeg County and Champooick County, and named after Francis Marion.
What is the county seat of Marion County?: The county seat of Marion County is Salem.
Is there an online parcel map for Marion County?: Yes. Marion County publishes a parcel map of 115,870 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 1843 from Champoeg County and Champooick County. Since then the Atlas of Historical County Boundaries records 8 later changes, chiefly involving Linn County, Champoeg County and Champoeg District. It was formerly called Champoeg District and Champoeg.
Who issues building permits in Marion County?: The county's page on building permits: MCPWTranspPermits@co.marion.or.us. Inside a city or town, ask that city first.
Who issues septic and well permits in Marion County?: The county's page on septic systems and wells: Health Services.
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