Onida is a city in and the county seat of Sully County, South Dakota, United States. Landmarks include Sully County Courthouse and L.E. Snyder House. Onida is the birthplace of Curt Byrum, professional golfer.
- CountySully County
- Population666 (2020 U.S. Census)
- Named forOneida
- Historic places2 on the National Register



























Sully County Courthouse
L.E. Snyder House
A view of Onida