County · code 41031
Jefferson CountyOregon
Jefferson County is in Oregon and has its seat in Madras. The county was formed on December 12, 1914, and named after Mount Jefferson.
- Founded1914
- County seatMadras
- Named forMount Jefferson, Oregon
- Land area1,782 sq mi + 10 sq mi water
- Population24,502 2020 Census
Where it is
Jefferson on the map of Oregon
Oregon has 36 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1914 from Crook County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Jefferson County was created from Crook County, with the creation authorized at the general election of November 3, 1912, and becoming effective by Governor's proclamation on December 12, 1914.
- 1914Jefferson County created Jefferson created from Crook. Jefferson creation authorized at the general election of 3 November 1912 and became effective by Governor's proclamation on 12 December 1914. · Ore. Laws 1915, gen., 28th reg. sess., Gov. Proc., pp. 9-10
- 1927Boundary clarified Jefferson redefined (no change).no change· Ore. Laws 1927, gen., 34th reg. sess., ch. 47/pp. 56-57
Land and parcels
What the maps cover in Jefferson
Who publishes each layer, how good it is, and when we last checked.
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Parcels Missing
No public parcel map found for Jefferson County yet. Lot lines and owners of record are kept by the county (co.jefferson.or.us).
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Address points Official
One point per address, 10,536 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
Jefferson 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
Jefferson County's official site
We have found the county's site but not its offices yet; start there.
County government
- County government
The official website of Jefferson County.
See your own lot on these maps
Open Jefferson 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 Jefferson County
- When was Jefferson County founded?
- Jefferson County was founded in 1914, formed from Crook County, and named after Mount Jefferson, Oregon.
- What is the county seat of Jefferson County?
- The county seat of Jefferson County is Madras.
- Is there an online parcel map for Jefferson County?
- Not that we have found yet. Lot lines and owners of record are kept by the county assessor's office. When a public parcel map appears, it shows here.
- Has Jefferson County's boundary or name changed?
- Jefferson County was created in 1914 from Crook County. Its boundary has been clarified one time since, with no change on the ground.
- Is my lot in a flood zone?
- We do not have flood maps for Jefferson County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby