Time in South Dakota Time in South Dakota South Dakota lies in both the Mountain Time Zone and the Central Time Zone. Mountain Time roughly contains the western half of the state, but not all of it. Rapid City is the largest city in the Mountain Time portion of the state. Central Time contains the eastern half of the state and roughly more of the state than the Mountain Time Zone and includes the state capital Pierre and the largest city, Sioux Falls. The 2 zones for South Dakota as given by zone.tab of the IANA time zone database. Columns marked * are from
South Dakota Highway 79 with U.S. Route 212 south of Newell. Near North Dakota, the highway passes through the South Dakota portion of Custer National Forest. SD 79 then joins SD 20 for a short concurrent run, and finally turns northward until it reaches North Dakota. South Dakota Highway 79 South Dakota Highway 79 (SD 79) is a state highway in the U.S. state of South Dakota. It runs from Maverick Junction near the Black Hills National Forest to the North Dakota state line. SD 79's southern terminus is at Maverick Junction near Hot Springs, where it meets US 18 and US 385. SD