County · code 46041
Dewey CountySouth Dakota
Dewey County is a county in South Dakota, with its seat in Timber Lake. The county was established in 1883.
- Founded1883
- County seatTimber Lake
- Land area2,302 sq mi + 143 sq mi water
- Population5,239 2020 Census
- Parcels mapped12,574 checked 16 October 2026
Where it is
Dewey on the map of South Dakota
South Dakota has 66 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Founded in 1883
An old deed may name a county that no longer exists, or a boundary that has since moved.
Dewey County was formed in 1883 when Rusk County was renamed Dewey, and it became a county in the state of South Dakota on November 2, 1889. The county lost territory to Corson County in 1909, and gained from Armstrong County by 1911.
- 1883Renamed Rusk renamed Dewey.formerly Rusk· Dak. Terr. Laws 1883, 15th sess., ch. 17/p. 29
- 1889Became part of South Dakota Dewey became a county in the state of South Dakota. · U.S. Stat., vol. 25, ch. 180[1889]/pp. 676-684; U.S. Stat., vol. 26, no. 5/pp. 1548-1549; Swindler, 9:107-109; Van Zandt, 134
- 1895Changed Dewey attached to Walworth “for judicial purposes.” · S. Dak. Laws 1895, 4th sess., ch. 48/pp. 53-54
- 1909Lost territory Dewey lost to creation of Corson. · S. Dak. Laws 1909, 11th sess., ch. 133/p. 209
- 1910Changed Dewey fully organized, detached from Walworth. · Early History of South Dakota Counties, 29-30
- 1911Gained territory By 1 February 1911, Dewey gained from Armstrong (extinct) and gained part of Non-County Area 1 when boundaries were moved to run on federal land survey lines.from Armstrong· S. Dak. Laws 1911, 12th sess., ch. 107/p. 137; S. Dak. Rev. Code 1919, 1:142, 145
- 1953Gained territory Dewey gained all of Armstrong; Armstrong eliminated.from Armstrong· S. Dak. Laws 1951, 32d sess., ch. 37/p. 38; S. Dak. Code 1939, 1:339
Land and parcels
What the maps cover in Dewey
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 12,574 parcels from Dewey County. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
edited 30 September 2026 · checked 16 October 2026 -
Address points Missing
No public address points layer found for Dewey 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
Dewey by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
See your own lot on these maps
Open Dewey 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 Dewey County
- When was Dewey County founded?
- Dewey County was founded in 1883.
- What is the county seat of Dewey County?
- The county seat of Dewey County is Timber Lake.
- Is there an online parcel map for Dewey County?
- Yes. Dewey County publishes a parcel map of 12,574 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Dewey County's boundary or name changed?
- Atlas of Historical County Boundaries records 7 changes for Dewey County. Since then the Atlas of Historical County Boundaries records 7 later changes, chiefly involving Armstrong County, Walworth County and Corson County. It was formerly called Rusk.
- Is my lot in a flood zone?
- We do not have flood maps for Dewey County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby