South Dakota Highway 37

South Dakota Highway 37
State	SD
Type	SD
Route	37
Length mi	286.250
Established	1926
Direction a	south
Terminus a	Nebraska
Direction b	north
Terminus b	North Dakota
Counties	Bon Homme County, Hanson County, Spink County, Hughes County, Codington County, Brown County

South Dakota Highway 37 is a primary north–south state highway traversing central and eastern South Dakota, connecting the Nebraska border near Bon Homme County to the North Dakota line near Groton. The route links a sequence of regional centers, rural townships, and agricultural districts, intersecting with federal routes such as U.S. Route 18, Interstate 90, and U.S. Route 12. The corridor serves freight movements, commuter traffic, and access to state facilities including sites near Pierre and Watertown.

Route description

The highway begins at the Nebraska boundary adjacent to rural sections near Bon Homme County and proceeds north through landscapes typified by the Missouri River valley and the Great Plains. It reaches Platte where it intersects U.S. Route 18 and provides connections toward Sioux Falls, Vermillion, and Sioux City. Continuing north, the route crosses agricultural belts into Huron-area corridors, meeting U.S. Route 14 and offering access eastward to Mobridge and westward to Pierre via linked routes.

Further north, the highway joins Interstate 90 near the Mitchell–Pierre corridor, creating interchange movements that connect freight bound for Rapid City and Sioux Falls. North of I‑90 it traverses through counties including Hughes County and nears the capital region around Pierre for indirect access. The route continues to Watertown, intersecting U.S. Route 212 and U.S. Route 81 movements to Fargo and Minneapolis. Near its terminus the highway reaches Groton and crosses into North Dakota, linking with cross‑border corridors toward Aberdeen and Grand Forks.

History

Established as part of the 1920s state route numbering initiative concurrent with national roadway standardizations, the highway’s alignment was influenced by railtowns served by carriers such as the Chicago and North Western Transportation Company, Milwaukee Road, and Union Pacific Railroad. Early paving projects followed New Deal era programs tied to agencies like the Works Progress Administration and coordination with federal initiatives under the Federal Highway Act of 1921. Post‑World War II improvements paralleled interstate development exemplified by Interstate construction; sections were realigned to create grade separations and faster connections to Interstate 90 and U.S. Route 12.

Significant mid‑century upgrades reflected agricultural mechanization trends linked to entities such as the United States Department of Agriculture and regional cooperative movements; bridges were replaced to meet standards promoted by the American Association of State Highway and Transportation Officials. Late 20th‑century projects included bypasses around small towns to improve safety and speed, echoing patterns seen on U.S. Route 81 and U.S. Route 281. More recent rehabilitation work has been funded through state bond measures overseen by the South Dakota Department of Transportation and federal surface transportation programs connected to acts like the Fixing America’s Surface Transportation Act.

Major intersections

The route intersects a series of principal corridors and interstates including: junctions with U.S. Route 18 near Platte; crossings of U.S. Route 14 close to Huron; an interchange with Interstate 90 near the Mitchell region; connections to U.S. Route 212 and U.S. Route 81 serving Watertown; and the northern terminus at the North Dakota state line providing continuity toward U.S. Route 2 and regional routes serving Grand Forks and Fargo. County road intersections link to county seats such as Bon Homme County seat, Hanson County seat, and Brown County seat.

Traffic and usage

Traffic volumes vary from rural low‑density segments serving farm equipment and grain shipments to higher AADT counts near interchanges with Interstate 90 and corridors feeding Watertown and Pierre. Freight movements include agricultural commodities destined for regional terminals tied to the BNSF Railway network and truck flows serving processors and elevators affiliated with cooperative chains like CHS Inc. and grain handlers. Seasonal tourist traffic en route to recreational resources such as the Missouri River and regional festivals in towns along the corridor also affects peak loads. Safety programs coordinated with the National Highway Traffic Safety Administration guide enforcement and infrastructure countermeasures where crash concentrations have been recorded.

Future developments

Planned improvements emphasize pavement rehabilitation, bridge replacements, and interchange upgrades driven by priorities set by the South Dakota Department of Transportation and regional planning commissions such as the Northeast Council of Governments. Proposals include capacity enhancements near growth nodes tied to economic development efforts by entities like the South Dakota Governor’s Office of Economic Development and investments aligned with federal grants from programs modeled after the Infrastructure Investment and Jobs Act. Long‑range planning contemplates multimodal links to rail interchanges operated by BNSF Railway and Union Pacific Railroad and potential safety realignments modeled on corridor improvements undertaken on U.S. Route 12 and U.S. Route 81.

Category:State highways in South Dakota