The following is a list of events of the year 1889 in South Dakota.
Incumbents State government Governor: Arthur C. Mellette (R) (starting November 2)
Events November 2 – The Dakota Territory is admitted to the union of the United States, with South Dakota becoming the 40th U.S state. October 1 – 1889 South Dakota gubernatorial election. November 2 – Arthur C. Mellette wins the gubernatorial election, becoming the first governor of South Dakota.
See also 1889 in the United States
References