State: | SD |
Type: | US |
Route: | 12 |
Map Custom: | yes |
Map Notes: | US 12 highlighted in red |
Length Mi: | 319.24 |
Length Ref: | [1] |
Established: | 1926 |
Direction A: | West |
Terminus A: | at the North Dakota state line |
Junction: | |
Direction B: | East |
Terminus B: | at the Minnesota state line |
Counties: | Perkins, Corson, Walworth, Edmunds, Brown, Day, Roberts, Grant |
Previous Type: | SD |
Previous Route: | 11 |
Next Type: | SD |
Next Route: | 12 |
U.S. Highway 12 (US 12) is a part of the United States Numbered Highway System that travels from Aberdeen, Washington, to Detroit, Michigan. In the state of South Dakota, US 12 extends from the North Dakota border east to the Minnesota border.
US 12 enters South Dakota from North Dakota as a rural two-lane highway about 10miles west-northwest of Lemmon before entering the Standing Rock Indian Reservation. For approximately the next 70miles, US 12 runs parallel to the border of North Dakota, sometimes within less than . At Walker, US 12 heads southeast for 37miles, where it crosses the Missouri River at Mobridge, exiting the reservation. From there, it continues east for 18miles, until it meets with US 83 near Selby. It overlaps US 83 for 7miles. After leaving US 83, it turns due east and spends about 80miles as a rural two-lane highway again. A few miles before reaching Aberdeen, it becomes an at-grade expressway. After the junction with US 281, it goes back to being two lanes for a few miles through Aberdeen and past Aberdeen Regional Airport, before once again becoming a four-lane expressway, until 2miles before Waubay. East of Waubay it becomes again an at-grade expressway until it meets with I-29 near Summit. The speed limit from Aberdeen to I-29 is 70mph except through the communities of Groton, Webster, and Waubay. From there, it heads southeast 22miles until Milbank. At Milbank, it continues east for 12miles, until it crosses into Minnesota at Big Stone City, just south of Big Stone Lake.[2]
The South Dakota section of US 12 is legally defined at South Dakota Codified Laws § 31-4-132.[3]