South Dakota Highway 20 (SD 20) 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 northern

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 ...

, United States, that connects the

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...

state line, west-southwest of Camp Crook, with 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 ...

state line, east-southeast of Revillo, via Buffalo,

Bison Bison are large bovines in the genus ''Bison'' (Greek: "wild ox" (bison)) within the tribe Bovini. Two extant and numerous extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North Ame ...

, Timber Lake, Mobridge,

Selby Selby is a market town and civil parish in the Selby District of North Yorkshire, England, south of York on the River Ouse, with a population at the 2011 census of 14,731. The town was historically part of the West Riding of Yorkshire until ...

, and

Watertown Watertown may refer to: Places in China In China, a water town is a type of ancient scenic town known for its waterways. Places in the United States *Watertown, Connecticut, a New England town **Watertown (CDP), Connecticut, the central village ...

. From Mobridge to the Walworth–Potter county line, this highway is part of the

Lewis and Clark Trail The Lewis and Clark National Historic Trail is a route across the United States commemorating the Lewis and Clark Expedition of 1804 to 1806. It is part of the National Trails System of the United States. It extends for some from Pittsburgh, Pen ...

. From about Timber Lake to just west of Mobridge, this highway is part of the Native American Scenic Byway. From the Montana state line to Camp Crook, the highway is a

dirt road A dirt road or track is a type of unpaved road not paved with asphalt, concrete, brick, or stone; made from the native material of the land surface through which it passes, known to highway engineers as subgrade material. Dirt roads are suitable ...

. SD 20 is composed of two disconnected segments. The longer western segment extends from Montana to Watertown. The much-shorter eastern segment extends from west of South Shore to Minnesota. However, 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 ...

previously indicated that SD 20 followed US 212, US 81, and Interstate 29 (I-29) between the two segments. SD 20 originally extended from SD 45 west of Cresbard to Watertown. It was extended west to U.S. Route 83, southwest of Lowry. Later, it was extended to its current eastern terminus. Later still, it was extended to its current western terminus, replacing what had been SD 8 (and later SD 18).

Route description

Harding County

SD 20 begins at an

intersection In mathematics, the intersection of two or more objects is another object consisting of everything that is contained in all of the objects simultaneously. For example, in Euclidean geometry, when two lines in a plane are not parallel, their i ...

with the eastern terminus of Tie Creek Road on the

state line west-southwest of Camp Crook, in the west-central part of Harding County. Here, the roadway continues to the south as Little Missouri Road. SD 20 travels to the north on the state line as a

. Approximately later, it curves to a due-east direction and enters Harding County and South Dakota proper. Almost immediately after entering Camp Crook, the highway's dirt portion ends. Just west of Park Avenue, it curves to the south. At an intersection with First Street East, it curves back to the east. Just after leaving Camp Crook, it crosses over the Little Missouri River. It then intersects the northern terminus of South Camp Crook Road, which leads to Sky Ranch and

Belle Fourche Belle Fourche (; ) is a city in and the county seat of Butte County, South Dakota, United States. Its population was 5,617 at the 2020 census. It is near the geographic center of the United States, which moved some 550 miles northwest from the g ...

. The highway curves to the east-northeast. SD 20 parallels a brief portion of Ash Creek. Farther to the east, it crosses over Graves Creek. Then, it parallels a brief portion of Brush Creek. It intersects the southern terminus of Clanton Road, which leads to Gardner Lake. Just before entering Buffalo, it crosses over Rush Creek. In the south-central part of the town, it intersects U.S. Route 85. The highways begin a

concurrency Concurrent means happening at the same time. Concurrency, concurrent, or concurrence may refer to: Law * Concurrence, in jurisprudence, the need to prove both ''actus reus'' and ''mens rea'' * Concurring opinion (also called a "concurrence"), a ...

to the south. Almost immediately, they leave Buffalo. They cross over the South Fork Grand River. When they split, SD 20 resumes its eastward direction. It curves to the east-southeast and crosses over Clarks Fork Creek. It intersects the northern terminus of Park Road, which leads to the

Antelope Range and Livestock Research Station The Antelope Range and Livestock Research Station is operated by South Dakota State University and its extension programs to improve ranching in the U.S. State of South Dakota. The site is large, the largest of SDSU's research stations. This land ...

. It curves to the east-northeast and enters

Custer National Forest Custer National Forest is located primarily in the south central part of the U.S. state of Montana but also has separate sections in northwestern South Dakota. With a total area of , the forest comprises over 10 separate sections. While in the wes ...

. The highway travels through Reva Gap and passes Flag Rock. It curves to the northeast and leaves the forest. Just before curving to the east, it passes the location of the

Battle of Slim Buttes The Battle of Slim Buttes was fought on September 9–10, 1876, in the Great Sioux Reservation between the United States Army and Miniconjou Sioux during the Great Sioux War of 1876. It marked the first significant victory for the army sinc ...

, a battle fought between the

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

and the

Sioux The Sioux or Oceti Sakowin (; Dakota language, Dakota: Help:IPA, /otʃʰeːtʰi ʃakoːwĩ/) are groups of Native Americans in the United States, Native American tribes and First Nations in Canada, First Nations peoples in North America. The ...

. It then begins a concurrency with SD 79. This intersection is also the southern terminus of Tickle Hill Place. The two highways travel through

Reva Reva may refer to: Places * Reva, Belgrade, urban neighborhood of Belgrade, Serbia * Reva, Mozambique, village in Ancuabe District in Cabo Delgado Province in northeastern Mozambique * Reva, Trebnje, small settlement just south of Dobrnič in the ...

. They curve to the east-southeast and then split. SD 20 curves to the southeast and then back to the east. At an intersection with 155th Avenue, it enters the west-central part of Perkins County.

Perkins County

SD 20 continues to the east and travels through Prairie City. Almost immediately, it crosses over the South Fork Thunder Butte Creek. Approximately east of Divide Road, it crosses over this creek again. At an intersection with the northern terminus of 170th Avenue, SD 20 meets the southern terminus of SD 75. The highway then enters the far northern part of

. The highway travels through

rural area In general, a rural area or a countryside is a geographic area that is located outside towns and cities. Typical rural areas have a low population density and small settlements. Agricultural areas and areas with forestry typically are descri ...

s of the county. It travels through

Meadow A meadow ( ) is an open habitat, or field, vegetated by grasses, herbs, and other non-woody plants. Trees or shrubs may sparsely populate meadows, as long as these areas maintain an open character. Meadows may be naturally occurring or artifi ...

and then intersects SD 73. The two highways travel concurrently to the south. When they split, they also meet the eastern terminus of Rolling Hills Road. SD 20 continues to the east. It travels just north of Coal Springs. A little ways east of 200th Avenue, it enters the northeast part of both

Ziebach County Ziebach County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 2,413. Its county seat is Dupree. It is the last county (or county equivalent) in the United States alphabetically. The county's per-capit ...

and the

Cheyenne River Indian Reservation The Cheyenne River Indian Reservation was created by the United States in 1889 by breaking up the Great Sioux Reservation, following the attrition of the Lakota in a series of wars in the 1870s. The reservation covers almost all of Dewey ...

Ziebach County

SD 20 curves to the southeast and then back to the east. It begins to curve back to the southeast just before traveling through Glad Valley. Just before Dorsey Road, it curves back to the east. It intersects SD 65 on the Ziebach– Dewey county line. The two highways travel concurrently to the east, on part of the county line. A short distance later, they enter Dewey County proper.

Dewey and Corson counties

SD 20 and SD 65 continue to the east. They skirt along the southern edge of Isabel Municipal Airport and then curve to the north. They enter the

city limits City limits or city boundaries refer to the defined boundary or border of a city. The area within the city limit can be called the city proper. Town limit/boundary and village limit/boundary apply to towns and villages. Similarly, corporate limi ...

Isabel Isabel is a female name of Spanish origin. Isabelle is a name that is similar, but it is of French origin. It originates as the medieval Spanish form of '' Elisabeth'' (ultimately Hebrew ''Elisheva''), Arising in the 12th century, it became popul ...

. They curve to the northeast, where they split. SD 20 curves to the east and leaves Isabel. It curves to the north and enters

Firesteel A fire striker is a piece of carbon steel from which sparks are struck by the sharp edge of flint, chert or similar rock. It is a specific tool used in fire making. History In early times, percussion fire making was often used to start fir ...

. It begins a curve to the east and leaves the community. It crosses the Little Moreau River, and almost immediately, intersects the southern terminus of County Road 243 (243rd Avenue) and SD 63. SD 20 and SD 63 begin to travel concurrently to the east. Just west of an intersection with 248th Avenue, they begin to curve to the east-northeast. They then enter Timber Lake. Almost immediately, they intersect the northern terminus of H Street, which leads to the Timber Lake Municipal Airport and the Little Moreau Recreation Area. In the north-central part of the city is an intersection with Main Street, which leads to the

business district A central business district (CBD) is the commercial and business centre of a city. It contains commercial space and offices, and in larger cities will often be described as a financial district. Geographically, it often coincides with the "city ...

. They leave Timber Lake and curve to the north. They then curve to the east and begin to travel on the Dewey– Corson county line, which is also the dividing line between the Cheyenne River and

Standing Rock The Standing Rock Reservation ( lkt, Íŋyaŋ Woslál Háŋ) lies across the border between North and South Dakota in the United States, and is inhabited by ethnic "Hunkpapa and Sihasapa bands of Lakota Oyate and the Ihunktuwona and Pabaksa ...

Indian reservations. They continue to the east through rural areas and then split, with SD 20 continuing to the east. Just west of the appropriately-named Lake Road, the highway travels just south of the Trail City Railroad Lake. It then travels through Trail City. SD 20 curves to the north-northeast, entering Corson County and Standing Rock Indian Reservation proper, and curves back to the east. It curves to the northeast and then to the north. It curves to the north-northeast and intersects US 12. The two highways travel concurrently to the southeast. They curve to the northeast and cross over Claymore Creek. They intersect SD 1806, which joins the concurrency. The three highways continue to the northeast and curve to the east-southeast, where SD 1806 leaves to the north. US 12 and SD 20 head to the southeast, skirting along the southern edge of the Indian Memorial Recreation Area. They cross over part of the Missouri River known as

Lake Oahe Lake Oahe () is a large reservoir behind Oahe Dam on the Missouri River; it begins in central South Dakota and continues north into North Dakota in the United States. The lake has an area of and a maximum depth of . By volume, it is the List of l ...

(signed as "Missouri River Lake Oahe") Here, they leave the Standing Rock Indian Reservation and enter the northwestern part of Walworth County.

Walworth and Potter counties

US 12 and SD 20 cross over some railroad tracks of BNSF Railway and curve to the south. During this curve, they enter Mobridge. Just south of 12th Street West, they curve to the southeast. Just south of 6th Street West, they curve to the east. At 4th Avenue East, SD 1804 joins the concurrency. It intersects Airport Road and Revheim Road, which lead to Mobridge Municipal Airport, the

South Dakota National Guard The South Dakota National Guard is part of the South Dakota Department of Military & Veterans Affairs. It was created in 1862 as the State Militia. Its headquarters is located in Rapid City, South Dakota. It consists of the South Dakota Army Natio ...

armory, and the Revheim Park Recreation Area. The highways then leave Mobridge. A short distance later, SD 1804 departs to the south, while US 12 and SD 20 continue to the east. Just to the east of 293rd Avenue is a crossing of Blanket Creek. They enter the northern part of Glenham. Immediately, they have an intersection with the southern terminus of Glenham Road, which leads to

Pollock Pollock or pollack (pronounced ) is the common name used for either of the two species of North Atlantic marine fish in the genus ''Pollachius''. ''Pollachius pollachius'' is referred to as pollock in North America, Ireland and the United Kingd ...

. Just to the east of Main Street, they leave Glenham and continue to the east. Just east of 305th Avenue, they intersect US 83, which joins the concurrency. The three highways curve to the southeast and then to the south. They then enter

. At an intersection with Scranton Street, they meet the western terminus of SD 130. Just south of Walworth Street, they cross over some railroad tracks of BNSF Railway and pass some

sewage disposal Sewage treatment (or domestic wastewater treatment, municipal wastewater treatment) is a type of wastewater treatment which aims to remove contaminants from sewage to produce an effluent that is suitable for discharge to the surrounding envir ...

ponds. Then, they leave Selby. Just before an intersection with 134th Street, US 12 splits off to the southeast, while US 83 and SD 20 turn right to the southwest. They curve back to the south. Between 136th and 137th streets, they cross over Rieger Creek. Just south of 139th Street, they curve to the southwest. Just northeast of 306th Avenue, they curve to the south. They intersect the eastern terminus of SD 144 (142nd Street). Just north of 144th Street, they curve to the south-southeast and cross over Swan Creek. Just north of 147th Street, they curve back to the south. At 148th Street, on the Walworth–

Potter A potter is someone who makes pottery. Potter may also refer to: Places United States *Potter, originally a section on the Alaska Railroad, currently a neighborhood of Anchorage, Alaska, US * Potter, Arkansas *Potter, Nebraska * Potters, New Je ...

county line, SD 20 splits off to the east, on the county line. Just east of 318th Avenue, it passes Hoven Municipal Airport. At 319th Avenue, SD 47 joins SD 20 in a concurrency to the east. Almost immediately, they enter Hoven. They pass a city park and then make a 90-degree curve to the south. They enter the main part of Hoven and Potter County proper. Between 3rd and 4th avenues, they pass a

bus station A bus station or a bus interchange is a structure where city or intercity buses stop to pick up and drop off passengers. While the term bus depot can also be used to refer to a bus station, it generally refers to a bus garage. A bus station is l ...

. Between 5th and 6th avenues, they pass Hoven High School. South of 7th Avenue, they leave Hoven and continue to the south. At an intersection with the eastern terminus of CR 819 (151st Street), SD 20 splits off to the east. It travels just to the south of

Tolstoy Count Lev Nikolayevich TolstoyTolstoy pronounced his first name as , which corresponds to the romanization ''Lyov''. () (; russian: link=no, Лев Николаевич Толстой,In Tolstoy's day, his name was written as in pre-refor ...

. At an intersection with 329th Avenue, it enters the northwestern part of Faulk County.

Faulk County

SD 20 curves to the southeast and travels through the northeastern part of Onaka. It then curves back to the east. Between 340th and 343rd avenues, it passes Clark Lake. Between 348th and 349th avenues, the highway travels just north of Norbeck. East of 357th Avenue, it intersects SD 45. This intersection is also the western terminus of CR 2-1 (152nd Street). The two highways travel concurrently to the south. They cross over the western part of Lake Cresbard. At an intersection with 154th Street, they split, with SD 20 heading to the east. Between 360th and 361st avenues, it crosses the North Fork Snake Creek. Then, it travels just south of Cresbard. Just west of 374th Avenue, the highway crosses over Perry Creek. Just west of 372nd Avenue, it travels just south of

Chelsea Chelsea or Chelsey may refer to: Places Australia * Chelsea, Victoria Canada * Chelsea, Nova Scotia * Chelsea, Quebec United Kingdom * Chelsea, London, an area of London, bounded to the south by the River Thames ** Chelsea (UK Parliament consti ...

. At an intersection with 373rd Avenue, it enters the northwestern part of Spink County.

Spink County

SD 20 heads to the east-northeast. East of 375th Avenue, it crosses over Snake Creek. Just west of CR 19 (378th Avenue), it crosses over this creek again. Just to the east of this intersection is a third crossing of this creek. At an intersection with 382nd Avenue, it curves to the east-southeast. East of this intersection, it enters the northern part of Northville. Between Front Street and 383rd Avenue, it crosses over some

railroad tracks A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepers, ...

Union Pacific Railroad The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

. The highway then leaves Northville. It intersects US 281 (386th Avenue) and then travels through the northern part of Mellette. Just east of the appropriately-named Railway Avenue, it crosses over some railroad tracks of

BNSF Railway BNSF Railway is one of the largest freight railroads in North America. One of seven North American Class I railroads, BNSF has 35,000 employees, of track in 28 states, and nearly 8,000 locomotives. It has three transcontinental routes that ...

. East of 391st Avenue, SD 20 crosses over the

James River The James River is a river in the U.S. state of Virginia that begins in the Appalachian Mountains and flows U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed April 1, 2011 to Chesapea ...

. Just east of 395th Avenue, it travels through the southern part of

Brentford Brentford is a suburban town in West London, England and part of the London Borough of Hounslow. It lies at the confluence of the River Brent and the Thames, west of Charing Cross. Its economy has diverse company headquarters buildings whi ...

. Just east of 399th Avenue, it crosses over Dry Run. East of 405th Avenue, the highway enters the southwestern part of Conde. It has an intersection with SD 37 and the western terminus of CR 6 (154th Street). SD 20 and SD 37 begin a concurrency to the south. CR 6 (154th Street) is signed as a

truck route A truck or lorry is a motor vehicle designed to transport cargo, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame constructi ...

. Almost immediately, SD 20 and SD 37 leave Conde. At an intersection with the eastern terminus of CR 8 (157th Street), the two highways split, with SD 20 continuing its eastward trek. Between 411th and 412th avenues, it enters the northwestern part of Clark County.

Clark County

SD 20 continues traveling in a roughly eastward direction. Just west of 421st Avenue, it curves to the east-southeast and then skirts along the northern edge of Crocker. The highway curves back to the east. East of 428th Avenue, it travels through the northern part of

Bradley Bradley is an English surname derived from a place name meaning "broad wood" or "broad meadow" in Old English. Like many English surnames Bradley can also be used as a given name and as such has become popular. It is also an Anglicisation of t ...

. East of 433rd Avenue, it intersects SD 25. At an intersection with 436th Avenue, which is northwest of

Wallace Wallace may refer to: People * Clan Wallace in Scotland * Wallace (given name) * Wallace (surname) * Wallace (footballer, born 1986), full name Wallace Fernando Pereira, Brazilian football left-back * Wallace (footballer, born 1987), full name ...

, it enters the northwestern part of

Codington County Codington County is a county in the U.S. state of South Dakota. As of the 2020 United States Census, the population was 28,325. Its county seat is Watertown. The county was created in 1877 and organized in 1878. It is named for Rev. George S. S ...

Codington County

SD 20 continues to the east and travels north of Wallace. East of 441st Avenue, and north of Grass Lake, the highway curves to the southeast. Just southeast of 444th Avenue and Sixth Street, it travels through the eastern part of

Florence Florence ( ; it, Firenze ) is a city in Central Italy and the capital city of the Tuscany region. It is the most populated city in Tuscany, with 383,083 inhabitants in 2016, and over 1,520,000 in its metropolitan area.Bilancio demografico an ...

. Between 161st Street and 445th Avenue, it skirts along the eastern edge of Dry Lake State Public Shooting Area. After it begins a curve to the south, it travels through the western part of the American Game Association State Public Shooting Area. South of 163rd Street, it curves to the southeast and travels just northeast of the Chain of Lakes. It curves to the south and intersects 450th Avenue north of

Lake Kampeska Lake Kampeska is a inland glacial lake in the U.S. state of South Dakota. It is located west-northwest of Watertown, South Dakota and lies entirely within Codington County and the Coteau des Prairies. The lake is naturally shaped and the most urba ...

. This road, which is

unsigned Unsigned can refer to: * An unsigned artist is a musical artist or group not attached or signed to a record label ** Unsigned Music Awards, ceremony noting achievements of unsigned artists ** Unsigned band web, online community * Similarly, the c ...

as SD 20P, leads to the path of former SD 139. It curves to the east-southeast and intersects North Lake Drive, which was the northern terminus of SD 139. The highway curves to the southeast and parallels part of the lake. It then intersects the northern terminus of South Lake Drive, which leads to Lake City Park. The highway then becomes a

divided highway A dual carriageway ( BE) or divided highway ( AE) is a class of highway with carriageways for traffic travelling in opposite directions separated by a central reservation (BrE) or median (AmE). Roads with two or more carriageways which are ...

and enters

. It immediately intersects the northern terminus of Airport Drive, which leads to Watertown Municipal Airport and the Lake Area Technical Institute's Aviation Annex. It then intersects Sioux Conifer Road, which leads to Big Sioux State Tree Nursery. Just southwest of 14th Avenue, the divided highway portion ends, and the traffic reverts to two-way traffic. Just before 10th Street Northwest, the highway curves to the south. It intersects 10th Avenue Northwest, which leads to Prairie Lakes Hospital. It passes the

Bramble Park Zoo Bramble Park Zoo is located in Watertown, South Dakota. Open since 1912, the zoo comprises with approximately 500 animals representing 130 different species. Bramble Park Zoo has been an accredited member of the Association of Zoos & Aquariums ...

. An intersection with Kemp Avenue West leads to the business district, the Watertown Stadium, and the Codington County Extension Center and Agricultural Building. It then intersects US 212 (9th Avenue South). Here, the western segment ends and the roadway continues as 20th Avenue South. Until March 2022, SDDOT indicated that SD 20 followed US 212 east in Watertown, US 81 from Watertown to northeast of Watertown, and Interstate 29 (I-29) and US 81 from there to just east of the western terminus of the eastern segment, west of South Shore. However, this implication was

. Officially, the eastern segment of SD 20 begins at an intersection with CR 11 (455th Avenue) and CR 2 (157th Street) west of South Shore in the northeastern part of Codington County. It travels to the east and has an interchange with I-29/US 81. East of 462nd Avenue, it curves to the southeast and crosses over some railroad tracks of BNSF Railway. It curves back to the east, just south of Punished Woman Lake and the South Punished Womans State Public Shooting Area. Almost immediately, it travels through South Shore. It travels between Larson State Public Shooting Area and Round Lake. Almost immediately, it enters the southwestern part of

Grant County Grant County may refer to: Places ;Australia * County of Grant, Victoria ;United States *Grant County, Arkansas *Grant County, Indiana *Grant County, Kansas *Grant County, Kentucky *Grant County, Minnesota *Grant County, Nebraska *Grant Co ...

Grant County

SD 20 continues to the east. Just west of CR 9 (468th Avenue), it crosses over some railroad tracks of BNSF Railway. Just west of 470th Avenue, it travels through the northern part of

Stockholm Stockholm () is the Capital city, capital and List of urban areas in Sweden by population, largest city of Sweden as well as the List of urban areas in the Nordic countries, largest urban area in Scandinavia. Approximately 980,000 people liv ...

. East of 477th Avenue, it intersects SD 15 (478th Avenue) and the western terminus of SD 158 (157th Street). At this intersection, SD 15 and SD 20 travel concurrently to the south. Just south of 161st Street, which is east-southeast of La Bolt, the two highways cross over some railroad tracks of BNSF Railway. South of 163rd Street, they cross over the

South Fork Yellow Bank River The Yellow Bank River is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed October 5, 2012 tributary of the Minnesota River in western Minnesota in the United States. It is formed by ...

. At an intersection with the eastern terminus of CR 20 (164th Street), SD 20 splits off to the east. Between 481st and 483rd avenues, the highway travels through the southern part of Revillo. East of 482nd Avenue, it crosses over Mud Creek. It continues to the east until it reaches the

state line. Here, it intersects 488th Avenue and ends. The roadway continues as Minnesota State Highway 40 (MN 40).

National Highway System

The only segment of SD 20 that is included as part of the National Highway System, a system of routes determined to be the most important for the nation's economy, mobility and defense, is the portion concurrent with US 12 and US 83 from west-northwest of Mobridge to southwest of Lowry.

History

SD 20 was established between 1929 and 1932. At this time, it extended from SD 45 west of Cresbard to Watertown. In the mid-1940s, it was extended westward to US 83 at the Walworth–Potter county line. By 1953, a short stub was established between Akaska and US 83. Also, north of Watertown, a stub was added between US 81's former path (current western terminus of the eastern segment) and what was US 77 (now SD 15). In 1954, the highway was extended further to the east, from US 77 and the Minnesota state line, as it currently does. In the late 1960s, the stub between Akaska and US 83 was redesignated as SD 20 Spur. At this time, the SD 20 mainline was extended to its current western terminus, absorbing what had been SD 8 and later SD 18.

Major intersections

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Related routes

Highway 20A

Highway 20A (SD 20A) was an

alternate route An official alternate route is a special route in the United States that provides an alternate alignment for a highway. They are loop roads and found in many road systems in the United States including the U.S. Highway system and various state an ...

of SD 20. It was established around 1970. It originally traveled on the current path of SD 20 east of SD 15 through the Revillo area. A few years later, it was shifted to travel between US 77/SD 20, north-northeast of La Bolt, to the

state line, northeast of Albee. This highway was decommissioned at the end of the decade and was redesignated as SD 158.

Akaska spur

Highway 20 Spur (SD 20 Spur) was a

spur route A spur route is a short road forming a branch from a longer, more important road such as a freeway, Interstate Highway, or motorway. A bypass or beltway should not be considered a true spur route as it typically reconnects with another or the s ...

of SD 20 that traveled from Akaska east to the SD 20 mainline. When this roadway was originally established in the early 1950s, it was part of the path of SD 20. It was redesignated as SD 20 Spur between 1965 and 1970, when SD 20 was shifted to its current path on U.S. Route 83 (US 83) in the area. The spur was further redesignated as SD 144 in 1976.

Watertown spur

Highway 20 Spur, officially Highway 20P (SD 20P), is a

of SD 20 that extends from the SD 20 mainline to the former SD 139, now known as North Lake Drive.

References

External links