County · code 46119
Sully CountySouth Dakota
Sully County is a county in South Dakota, with its seat in Onida. It was created in 1873 and named after Alfred Sully.
- Founded1873
- County seatOnida
- Named forAlfred Sully
- Land area1,007 sq mi + 63 sq mi water
- Population1,446 2020 Census
- Parcels mapped6,707 checked 15 October 2026
Where it is
Sully 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
Formed in 1873 from Buffalo County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Sully County was created by Dakota Territory in 1873 from Buffalo County. It became a county in the state of South Dakota in 1889.
- 1873Sully County created Sully created by Dakota Territory in present South Dakota from Buffalo. · Dak. Terr. Laws 1872, 10th sess., ch. 16, sec. 33/p. 37
- 1889Became part of South Dakota Sully 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
- 1917Boundary clarified Sully boundaries redefined (no change).no change· S. Dak. Laws 1917, 15th sess., reg., ch. 178/p. 235
Land and parcels
What the maps cover in Sully
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 6,707 parcels from Sully 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 Sully 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
Sully 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
Sully 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 Sully County.
See your own lot on these maps
Open Sully 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 Sully County
- When was Sully County founded?
- Sully County was founded in 1873, formed from Buffalo County, and named after Alfred Sully.
- What is the county seat of Sully County?
- The county seat of Sully County is Onida.
- Is there an online parcel map for Sully County?
- Yes. Sully County publishes a parcel map of 6,707 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Sully County's boundary or name changed?
- Sully County was created in 1873 from Buffalo County. Since then the Atlas of Historical County Boundaries records 1 later change.
- Is my lot in a flood zone?
- We do not have flood maps for Sully County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby