Interstate 90 (I-90) in the

US state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...

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 ...

traverses east–west through the southern half of the state.

Route description

I-90 enters South Dakota in Lawrence County as a four-lane divided highway. It enters concurrently with US Highway 14 (US 14) and passes through the town of

Spearfish Spearfish may refer to: Places *Spearfish, South Dakota, United States * North Spearfish, South Dakota, United States * Spearfish Formation, a geologic formation in the United States Biology * ''Tetrapturus'', a genus of marlin containing spe ...

, where it shares another concurrency with US 85 from exit 10 to exit 17. From there it passes several miles north and east of the tourist town of Deadwood before entering Meade County, going just to the west of Sturgis. Another concurrency is with

South Dakota Highway 34 South Dakota Highway 34 (SD 34) is a state route that runs parallel to Interstate 90 across the entire state of South Dakota. It begins at the Wyoming border west of Belle Fourche, as a continuation of Wyoming Highway 24 (WYO 24). The easte ...

(SD 34) from exit 23 at Whitewood to exit 30, the west exit of Sturgis, where there starts a concurrency with SD 79. The freeway generally passes along the north and east edges of the

Black Hills The Black Hills ( lkt, Ȟe Sápa; chy, Moʼȯhta-voʼhonáaeva; hid, awaxaawi shiibisha) is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black Elk P ...

. The route then enters Pennington County, where it passes through the northern edge of

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 ...

, gateway to the

and the nearest passing to

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, ...

, as well as other scenic attractions including

Custer State Park Custer State Park is a South Dakota State Park and wildlife reserve in the Black Hills, United States. The park is South Dakota's largest and first state park, named after Lt. Colonel George Armstrong Custer. The park covers an area of over of v ...

and the

Needles Highway South Dakota Highway 87 (SD 87) is a state highway in the southwestern part of the U.S. state of South Dakota. It travels through the Black Hills region. The highway's southern terminus is at an intersection with U.S. Route 385 ( ...

. Rapid City is also where the interstate has its westernmost auxiliary route,

I-190 Interstate 190 may refer to the following Interstate Highways in the United States related to Interstate 90: * Interstate 190 (Illinois), a spur into Chicago's O'Hare International Airport *Interstate 190 (Massachusetts), a spur from Worcester to L ...

, which links the Interstate to the western edge of the downtown area. SD 79's concurrency ends at exit 61 on the east side of the city. From Rapid City, the route heads east, passing between

Box Elder ''Acer negundo'', the box elder, boxelder maple, Manitoba maple or ash-leaved maple, is a species of maple native to North America. It is a fast-growing, short-lived tree with opposite, compound leaves. It is sometimes considered a weedy or inva ...

to the south and

Ellsworth Air Force Base Ellsworth Air Force Base (AFB) is a United States Air Force base located about northeast of Rapid City, South Dakota, just north of the town of Box Elder, South Dakota, Box Elder. The host unit at Ellsworth is the 28th Bomb Wing (28 BW). Assi ...

to the north before heading toward

Wall A wall is a structure and a surface that defines an area; carries a load; provides security, shelter, or soundproofing; or, is decorative. There are many kinds of walls, including: * Walls in buildings that form a fundamental part of the supe ...

on to Jackson County. Exits 110 and 131 for

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 ...

to the south ( SD 240) are within either way of the county line. The concurrency for US 14 ends at exit 112 just east of Wall; here, US 14 runs due east and will connect to the city of

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 ...

and the capital city of

Pierre Pierre is a masculine given name. It is a French form of the name Peter. Pierre originally meant "rock" or "stone" in French (derived from the Greek word πέτρος (''petros'') meaning "stone, rock", via Latin "petra"). It is a translation ...

From there, the route passes mostly east–west through Jackson and

Jones Jones may refer to: People *Jones (surname), a common Welsh and English surname *List of people with surname Jones * Jones (singer), a British singer-songwriter Arts and entertainment * Jones (''Animal Farm''), a human character in George Orwell ...

counties. There are short concurrencies with SD 73 (from the west entering Kadoka) and SD 63 in Jackson County. I-90 crosses the

Central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

–

Mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited Summit (topography), summit area, and ...

timezone boundary on the west edge of Jones County between milemarkers 174 and 175. Then, at Murdo, a concurrency begins with US 83 at exit 192 and continues to exit 212. It is in

Lyman County Lyman County is a county located in the U.S. state of South Dakota. As of the 2020 census, the population was 3,718. Its county seat is Kennebec. Lyman County was created by the Dakota Territorial Legislature on January 8, 1873, but was not o ...

, at exit 212 in Vivian, that the highway provides its closest link to the capital of

, along US 83, some north. The road crosses the Missouri River at

Lake Francis Case Lake Francis Case is a large reservoir impounded by Fort Randall Dam on the Missouri River in south-central South Dakota, United States. The lake has an area of and a maximum depth of . Lake Francis Case has a length of approximately and has a ...

, between the towns of Oacoma and

Chamberlain Chamberlain may refer to: Profession *Chamberlain (office), the officer in charge of managing the household of a sovereign or other noble figure People *Chamberlain (surname) **Houston Stewart Chamberlain (1855–1927), German-British philosop ...

, also crossing into

Brule County Brule County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 5,247. Its county seat is Chamberlain. History Brule County was created on January 14, 1875, of territory partitioned from Charles Mix County ...

. I-90 Business (I-90 Bus.) runs from exit 260 at Oacoma to downtown Chamberlain across the Missouri River on the nearby Chamberlain Bridge and returns to I-90 at exit 265. Beginning there is a short concurrency with SD 50 heading to Pukwana, and also in Brule County is another short concurrency with SD 45 starting at Kimball. I-90 then continues through Aurora County (connecting to White Lake and Plankinton), Davison County (where Mt. Vernon,

Mitchell Mitchell may refer to: People *Mitchell (surname) *Mitchell (given name) Places Australia * Mitchell, Australian Capital Territory, a light-industrial estate * Mitchell, New South Wales, a suburb of Bathurst * Mitchell, Northern Territo ...

, and the

Corn Palace The Corn Palace, commonly advertised as The World's Only Corn Palace and the Mitchell Corn Palace, is a multi-purpose arena/facility located in Mitchell, South Dakota, United States. The Moorish Revival building is decorated with crop art; the mu ...

are located), Hanson County (

Alexandria Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandria ...

), and McCook County ( Salem). Then comes the state's most populous county,

Minnehaha Minnehaha is a Native American woman documented in Henry Wadsworth Longfellow's 1855 epic poem ''The Song of Hiawatha''. She is the lover of the titular protagonist Hiawatha and comes to a tragic end. The name, often said to mean "laughing wat ...

. After passing the communities of Humboldt and

Hartford Hartford is the capital city of the U.S. state of Connecticut. It was the seat of Hartford County until Connecticut disbanded county government in 1960. It is the core city in the Greater Hartford metropolitan area. Census estimates since the ...

, the Interstate intersects the only other major Interstate in the state,

I-29 Interstate 29 (I-29) is an Interstate Highway in the Midwestern United States. I-29 runs from Kansas City, Missouri, at a junction with I-35 and I-70, to the Canada–US border near Pembina, North Dakota, where it connects with Manitoba P ...

, at

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 ...

, the largest city. Just east of I-29 is where I-90 meets the northern terminus of I-229. East of

Brandon Brandon may refer to: Names and people *Brandon (given name), a male given name *Brandon (surname), a surname with several different origins Places Australia *Brandon, a farm and 19th century homestead in Seaham, New South Wales *Brandon, Q ...

and northeast of Valley Springs, it then ends its trip through South Dakota of before entering

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 ...

and Rock County, just west of the towns of Beaver Creek and Manley. Since April 2015, the speed limit is , except it is between I-229 and Marion Road in Sioux Falls and through Rapid City. The speed limit remains between Rapid City and the

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

state line.

Codified law

The South Dakota section of I-90 is defined at South Dakota Codified Laws § 31-4-184.

History

I-90 was constructed in the 1970s. The four-lane Interstate replaced old US 16 as the main road connecting Rapid City and Sioux Falls. Much of Old US 16 remains intact; however, I-90 has absorbed sections and likewise has reshaped the economies of many southern South Dakota towns. The final section of I-90 in the state opened in November 1976 between the Wyoming state line and Spearfish. On May 24, 2012, the South Dakota Transportation Commission declared the entire length of I-90 as part of the National Purple Heart Trail, naming it the Purple Heart Memorial Highway, named after the military decoration of the same name.

Removal of exit 66

In the city of

, exit 66, which crossed SD 435, was closed on October 1, 2003, after a 10-month delay. The exit was closed and removed as a result of the

South Dakota Department of Transportation The South Dakota Department of Transportation (SDDOT) is a state government organization in charge of maintaining public roadways of the U.S. state of South Dakota. South Dakota has 82,447 miles of highways, roads and streets, as well as 5,905 br ...

(SDDOT)'s efforts to move traffic away from a potential crash site at the end of the

Ellsworth AFB Ellsworth Air Force Base (AFB) is a United States Air Force base located about northeast of Rapid City, South Dakota, just north of the town of Box Elder, South Dakota, Box Elder. The host unit at Ellsworth is the 28th Bomb Wing (28 BW). Assi ...

runway. The partial cloverleaf interchange of exit 66 was also demolished shortly thereafter. Exit 67, which was constructed not too long before the closure of exit 66, is now used as the main entrance and exit feeder to the base, and it is less likely to be impacted by a potential crash. Local citizens and officials feared the lack of entrances which access the Ellsworth AFB would cause traffic issues and moving businesses from near the old exit would cause some to close and affect tax revenue. Land near exit 66 began to be purchased in 2004, including the former

McDonald's McDonald's Corporation is an American Multinational corporation, multinational fast food chain store, chain, founded in 1940 as a restaurant operated by Richard and Maurice McDonald, in San Bernardino, California, United States. They rechri ...

property.

Exit list

References

External links