County · code 26161
Washtenaw CountyMichigan
Washtenaw County is a county in Michigan with its seat in Ann Arbor, formed in 1822.
- Founded1822
- County seatAnn Arbor
- Land area706 sq mi + 16 sq mi water
- Population372,258 2020 Census
Where it is
Washtenaw on the map of Michigan
Michigan has 83 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1822 from Monroe County, Oakland County and Wayne County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Washtenaw County was created by Michigan Territory on September 10, 1822, from Monroe, Oakland, and Wayne counties. Initially not fully organized, it was attached to Wayne County for administrative and judicial purposes until December 31, 1826, when it was fully organized and detached from Wayne. Between 1829 and 1837, Washtenaw County lost territory to the creation of Ingham, Jackson, and Livingston counties, though portions of these new counties were temporarily attached to Washtenaw for judicial purposes as they were organized.
- 1822Washtenaw County created Washtenaw created by Michigan Territory from Monroe, Oakland, and Wayne; Washtenaw not fully organized, attached to Wayne for administrative and judicial purposes. · Terr. Papers U.S., 11: 311
- 1826
- 1829Lost territory Washtenaw lost to creation of Ingham and Jackson. · Mich. Terr. Laws, 2:secs. 2, 5/p. 735
- 1829
- 1833Lost territory Washtenaw lost to creation of Livingston; Livingston not fully organized, part attached to Washtenaw "for judicial purposes." · Mich. Terr. Laws, 3:993
Show all 8 changes
- 1822Washtenaw County created Washtenaw created by Michigan Territory from Monroe, Oakland, and Wayne; Washtenaw not fully organized, attached to Wayne for administrative and judicial purposes. · Terr. Papers U.S., 11: 311
- 1826
- 1829Lost territory Washtenaw lost to creation of Ingham and Jackson. · Mich. Terr. Laws, 2:secs. 2, 5/p. 735
- 1829
- 1832
- 1833Lost territory Washtenaw lost to creation of Livingston; Livingston not fully organized, part attached to Washtenaw "for judicial purposes." · Mich. Terr. Laws, 3:993
- 1836Changed Livingston fully organized, detached from Washtenaw. · Mich. Acts 1836, ann. sess., p. 65
- 1837
Land and parcels
What the maps cover in Washtenaw
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 Washtenaw County yet. Lot lines and owners of record are kept by the county (washtenaw.org).
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Address points Missing
No public address points layer found for Washtenaw 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
Washtenaw 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
Washtenaw 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 Washtenaw County.
See your own lot on these maps
Open Washtenaw 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 Washtenaw County
- When was Washtenaw County founded?
- Washtenaw County was founded in 1822, formed from Monroe County, Oakland County and Wayne County.
- What is the county seat of Washtenaw County?
- The county seat of Washtenaw County is Ann Arbor.
- Is there an online parcel map for Washtenaw 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 Washtenaw County's boundary or name changed?
- Washtenaw County was created in 1822 from Monroe County, Oakland County and Wayne County. Since then the Atlas of Historical County Boundaries records 7 later changes, chiefly involving Jackson County, Ingham County and Livingston County.
- Is my lot in a flood zone?
- We do not have flood maps for Washtenaw County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby