These tables are historical listings of state senators who served in the South Dakota Senate from statehood in 1889 until the present.
45 senators elected from 41 districts. Senators were elected from single-member districts, with five counties each electing two at-large senators. The number of senators was reduced to 43 senators from 1893 to 1899. A 42nd District was added in 1909.
35 senators elected from 33 districts. Three counties each elected two at-large senators.
35 senators elected from 35 single-member districts. From 1967 to 1973, there were only 29 districts, with three counties each electing more than one at-large member. District 29 was eliminated from 1973 to 1985, when it became District 11's fifth at-large seat. In 1985, all remaining multi-member districts were eliminated, establishing the current 35 single-member districts.