US 18 in South Dakota

US 18 in South Dakota


US 18
Begin Edgemont
End Canton
Length 446 mi
Length 718 km

Hot Springs

Pine Ridge




Lake Andes






US 18 is a US Highway in the US state of South Dakota. The road forms an east-west route through the south of the state, from the Wyoming border to the Iowa border. The road visits few larger towns and is 718 kilometers long.

Travel directions

US 18 in Wyoming comes from Douglas and heads east through the south of the Black Hills. The only larger town in this wide region is Hot Springs. Perhaps somewhat surprising, the double numbering with US 385 is a divided highway with 2×2 lanes. The route then heads east through Native American reservations through sparsely populated land west of the Missouri River. Almost on the border with Nebraska, the Missouri is crossed, after which US 18 enters a more populated area, with more farms, villages and roads, although US 18 does not reach larger places. In eastern South Dakota one crosses Interstate 29, after which the US 18 in Iowacontinues towards Sheldon.

  • ANSWERMBA: Provides information about South Dakota overview.


US 18 at Edgemont.

US 18 was created in 1926. The route through South Dakota has not been significantly modified since then. The road is not very important to South Dakota, although it is the only east-west route, especially west of the Missouri River, but larger towns are hardly on it. Between 2011 and 2013, the section between Oelrichs and Hot Springs was widened to 2×2 lanes. This section is part of the Heartland Expressway, which runs north-south and piggybacks on US 18.

Traffic intensities

Every day 1,200 vehicles drive on the border with Wyoming, rising to 2,400 vehicles on the double numbering with US 385. More east the intensities vary, there are pieces with just 400 to 600 vehicles, but also for example 7,000 vehicles at Pine Ridge and 4,100 vehicles at Mission. 7,300 vehicles drove through Winner and 1,000 vehicles crossed the Missouri River daily. Further east, only 300 to 1,100 vehicles drive, mainly because US 18 does not serve larger towns here and has competition from parallel east-west routes. 1,900 vehicles crossed the Iowa border daily.

US 18 in South Dakota