South Dakota Highway 40 (SD 40) is a

state highway A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either ''numbered'' or ''maintained'' by a sub-national state or province. A road numbered by a ...

in southwestern part of the US state of

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...

. The highway is just over long and runs from U.S. Route 16A (US 16A) in Keystone to Bureau of Indian Affairs Highway 41 (BIA 41) in Red Shirt. The highway runs near

Mount Rushmore National Memorial Mount Rushmore National Memorial is a national memorial centered on a colossal sculpture carved into the granite face of Mount Rushmore (Lakota: ''Tȟuŋkášila Šákpe'', or Six Grandfathers) in the Black Hills near Keystone, South Dakota, ...

in Keystone, and its eastern terminus is on the

Pine Ridge Indian Reservation The Pine Ridge Indian Reservation ( lkt, Wazí Aháŋhaŋ Oyáŋke), also called Pine Ridge Agency, is an Oglala Lakota Indian reservation located entirely within the U.S. state of South Dakota. Originally included within the territory of the Gr ...

near the edge of

Badlands National Park Badlands National Park ( lkt, Makȟóšiča) is an American national park located in southwestern South Dakota. The park protects of sharply eroded buttes and pinnacles, along with the largest undisturbed mixed grass prairie in the United State ...

Route description

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 Black Hills National Forest is located in southwestern South Dakota and northeastern Wyoming, United States. The forest has an area of over 1.25 million acres (5,066 km²) and is managed by the Forest Service. Forest headquarters are locate ...

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 Buffalo Gap National Grassland is a National Grassland located primarily in southwestern South Dakota, United States. It is also the second largest National Grassland, after Little Missouri National Grassland in North Dakota. Characteristics of t ...

. Finally, the route curves to the south and crosses the

Cheyenne River The Cheyenne River ( lkt, Wakpá Wašté; "Good River"), also written ''Chyone'', referring to the Cheyenne people who once lived there, is a tributary of the Missouri River in the U.S. states of Wyoming and South Dakota. It is approximately 2 ...

; doing this, it leaves the Buffalo Gap National Grassland and Custer County, and enters

Oglala Lakota County Oglala Lakota County (known as Shannon County until May 2015) is a county in southwestern South Dakota, United States. The population was 13,672 at the 2020 census. Oglala Lakota County does not have a functioning county seat; Hot Springs in ne ...

and the

, becoming BIA 41. The route of SD 40 is defined in South Dakota Codified Laws § 31-4-161.

History

SD 40 was first established along the route from

Rapid City Rapid City ( lkt, link=no, Mni Lúzahaŋ Otȟúŋwahe; "Swift Water City") is the second most populous city in South Dakota and the county seat of Pennington County. Named after Rapid Creek, where the settlement developed, it is in western So ...

to the

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

border southeast of

Sioux Falls Sioux Falls () is the most populous city in the U.S. state of South Dakota and the 130th-most populous city in the United States. It is the county seat of Minnehaha County and also extends into Lincoln County to the south, which continues up t ...

in 1926. The section east of near

Philip Philip, also Phillip, is a male given name, derived from the Greek (''Philippos'', lit. "horse-loving" or "fond of horses"), from a compound of (''philos'', "dear", "loved", "loving") and (''hippos'', "horse"). Prominent Philips who popularize ...

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. SD 40 was rerouted southeast to east of

Witten Witten () is a city with almost 100,000 inhabitants in the Ennepe-Ruhr-Kreis (district) in North Rhine-Westphalia, Germany. Geography Witten is situated in the Ruhr valley, in the southern Ruhr area. Bordering municipalities * Bochum * Dortmu ...

, 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.

Major intersections

Related route

South Dakota Highway 40A (SD 40A) was a short spur route in the east part of

. This route was originally part of SD 40. At that time, SD 40 exited the park to the northeast, and continued east with US 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 US 16A. In 1976, this route was redesignated as

South Dakota Highway 377 South Dakota Highway 377 (SD 377) is a state highway in Jackson County, South Dakota, United States. It begins at an intersection with SD 44 in Interior, and travels in a northeasterly direction to its northern terminus at the I ...

References

External links