South Dakota Highway 40

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search

Highway 40 marker

Highway 40
Route of SD 40 (in red)
Route information
Defined by SDCL §31-4-161
Maintained by SDDOT
Length37.369 mi[1] (60.140 km)
Major junctions
West end US 16A in Keystone
  SD 79 in Hermosa
East endBureau of Indian Affairs Highway 41 in Red Shirt
CountiesPennington, Custer, Oglala Lakota
Highway system
  • South Dakota Highways
SD 38SD 42

South Dakota Highway 40 (SD 40) is a state highway in southwest South Dakota. The highway is just over 37 miles (60 km) long and runs from U.S. Route 16A (US 16A) in Keystone to Bureau of Indian Affairs Highway 41 in Red Shirt. The highway runs near Mount Rushmore National Memorial in Keystone, and its eastern terminus is on the Pine Ridge Indian Reservation near the edge of Badlands National Park.


SD 40 was first established along the route from Rapid City to the Minnesota border southeast of Sioux Falls in 1926.[2][3] The section east of near Philip was cosigned with US 16 when the U.S. Highway System was created. The SD 40 designation was dropped from the section east of Philip in 1927.[4] SD 40 was rerouted southeast to east of Witten, replacing the part of SD 44. SD 40 became part of an extended SD 44 by 1975. SD 40 was established along its current route in 1976.

Route description[edit]

SD 40 begins at an intersection with US 16A in Keystone and heads east through the town. It crosses Battle Creek numerous times, then leaves Keystone and heads in a general southeastern direction, curving regularly. The highway crosses Iron Creek just before leaving the Black Hills National Forest and crossing Battle Creek once more. It continues southeast, leaving Pennington County and entering Custer County. In Custer County, SD 40 meets SD 79, and the two highways run northward toward Hermosa. They straddle the western limit of Hermosa for a short distance before SD 79 continues north and SD 40 splits off to the east, passing through Hermosa. East of town, SD 40 curves back to the southeast and enters the Buffalo Gap National Grassland. Finally, the route curves to the south and crosses the Cheyenne River; doing this, it leaves the Buffalo Gap National Grassland and Custer County, and enters Oglala Lakota County and the Pine Ridge Indian Reservation, becoming Bureau of Indian Affairs Highway 41 (BIA Hwy. 41).[5]

Major intersections[edit]

PenningtonKeystone0.0000.000 US 16AWestern terminus
Custer15.58525.082 SD 79 southSouthern end of SD 79 concurrency
Hermosa15.89525.581 SD 79 northNorthern end of SD 79 concurrency
Oglala LakotaRed Shirt37.36960.140BIA Hwy. 41End state maintenance
1.000 mi = 1.609 km; 1.000 km = 0.621 mi

Related route[edit]

Highway 40A
LocationBadlands National Park
Length2.0 mi (3.2 km)

South Dakota Highway 40A was a short spur route in the east part of Badlands National Park. This route was originally part of South Dakota Highway 40. At that time, SD 40 exited the park to the northeast, and continued east with U.S. Highway 16. Around 1970, SD 40 was rerouted south from the park to a new alignment south of the White River. When this was done, SD 40A was created to link with Alternate U.S. Highway 16.

In 1976, this route was redesignated as South Dakota Highway 377.

Legal definition[edit]

The route of SD 40 is defined in South Dakota Codified Laws § 31-4-161. [1]


  1. ^ a b "State Highway Log: Rapid City Region" (PDF). South Dakota Department of Transportation. January 2012. Retrieved December 24, 2013.
  2. ^ Missing or empty |title= (help)
  3. ^ Missing or empty |title= (help)
  4. ^;sort:Pub_List_No_InitialSort%2CPub_Date%2CPub_List_No%2CSeries_No;lc:RUMSEY~8~1&mi=132&trs=138. Missing or empty |title= (help)
  5. ^ Google (December 24, 2013). "South Dakota Highway 40" (Map). Google Maps. Google. Retrieved December 24, 2013.

External links[edit]

Route map:

KML is from Wikidata