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 Provincial Trunk Highway 75 (PTH 75), which continues on to Winnipeg. The road follows the course of three major rivers, all of which form the borders of US states. The southern portion of I-29 closely parallels the Missouri River from Kansas City northward to Sioux City, Iowa, where it crosses and then parallels the Big Sioux River. For the northern third of the highway, it closely follows the Red River of the North. The major cities that I-29 connects to includes Council Bluffs, Iowa; Sioux City, Iowa; Sioux Falls, South Dakota; Fargo, North Dakota; and Grand Forks, North Dakota. I-29 also serves as a road connection between the four largest public universities in the Dakotas: the University of North Dakota, North Dakota State University, the University of South Dakota, and South Dakota State University.
South Dakota Highway 10 (SD 10) is a 175.945-mile (283.156 km) state highway in the north-central and northeastern portions of South Dakota, United States. It connects SD 1804 in Pollock with the Minnesota state line southeast of Sisseton.
South Dakota Highway 44 (SD 44) is a state highway in southern South Dakota that runs from U.S. Route 385 (US 385) west of Rapid City to Interstate 29 (I-29) south of Sioux Falls. It is just more than 379 miles (610 km) long.
South Dakota Highway 43 (SD 43) is a 1.131-mile-long (1.820 km) state highway that exists entirely in the southern part of Gregory County in the southern part of the U.S. state of South Dakota. It begins as an extension of Nebraska Highway 11 (N-11) at the Nebraska state line south of Fairfax. It travels northwest to an intersection with U.S. Route 18 (US 18) south-southwest of the town.
South Dakota Highway 47 is a state route that runs north to south across the central portion of South Dakota. It begins at an unnumbered highway at the North Dakota border north of Eureka, and ends at the Nebraska border, where it becomes Nebraska Highway 137. It is just under 241 miles (388 km) in length.
South Dakota Highway 22 (SD 22) is a 48.546-mile-long (78.127 km) state highway in Hamlin and Deuel counties in South Dakota, United States. It connects Hazel and Clear Lake.
South Dakota Highway 53 is a state route that runs north to south across south central South Dakota. It consists of two separate segments:
South Dakota Highway 26 (SD 26) is a 49.540-mile-long (79.727 km) state highway in the central part of the U.S. state of South Dakota. It connects rural areas of Hyde, Hand, and Spink counties.
South Dakota Highway 28 (SD 28) is a 105.937-mile (170.489 km) state highway in the east-central South Dakota, United States, that connects Hitchcock, Estelline, and Toronto.
South Dakota Highway 17 (SD 17) is a 1-mile-long (1.6 km) state highway in southeastern South Dakota, United States. It runs along the eastern edge of Lennox. SD 17 formerly continued south to what is now SD 46 near Centerville, and north to SD 42 west of Sioux Falls.
South Dakota Highway 19 (SD 19) is a 86.974-mile (139.971 km) state highway in southeastern South Dakota, United States. It connects the Nebraska state line, south of Vermillion, with the southeastern part of the Madison area, via Viborg, Hurley, Parker, and Humboldt. SD 19 formerly entered Centerville, but was shifted to the south. Its former path was redesignated as SD 19A. Its former southern terminus was at Vermillion, but was extended when a new bridge from Nebraska opened.
South Dakota Highway 20 (SD 20) is a 385.079-mile (619.725 km) state highway in northern South Dakota, United States, that connects the Montana state line, west-southwest of Camp Crook, with the Minnesota state line, east-southeast of Revillo, via Buffalo, Bison, Timber Lake, Mobridge, Selby, and Watertown. From Mobridge to the Walworth–Potter county line, this highway is part of the Lewis and Clark Trail. 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.
South Dakota Highway 73 is a state route that runs across western South Dakota. It begins at the Nebraska border, north of Merriman, Nebraska, as a continuation of Nebraska Highway 61. It runs to the North Dakota border, where it continues as North Dakota Highway 49. It is just more than 255 miles (410 km) in length.
South Dakota Highway 37 is a state route that runs across eastern South Dakota. It begins at the Nebraska border northeast of Niobrara, Nebraska, as a continuation of Nebraska Highway 14. It runs to the North Dakota border north of Hecla, where it continues as North Dakota Highway 1. It is 242 miles (389 km) in length.
South Dakota Highway 42 (SD 42) is a segmented state highway in southeastern South Dakota, United States. The first segment is a six-mile-long (9.7 km) highway in Aurora County. The second and longest is 60 miles (97 km) long and connects Ethan and Sioux Falls. The final segment connects Sioux Falls to Iowa Highway 9 southeast of Rowena.
South Dakota Highway 40 (SD 40) is a state highway in southwestern part of the US state of 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 (BIA 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.
South Dakota Highway 258 (SD 258) is a 2.552-mile-long (4.107 km) state highway in Aurora County, South Dakota. It runs from Interstate 90 (I-90) to U.S. Route 281, and is maintained by the South Dakota Department of Transportation (SDDOT). The route is not a part of the National Highway System.
South Dakota Highway 1804 (SD 1804) is a 126.745-mile-long (203.976 km) state highway in the U.S. state of South Dakota.
South Dakota Highway 63 (SD 63) is a 167.455-mile (269.493 km) state highway in central South Dakota, United States, that connects U.S. Route 18 (US 18) south-southeast of Parmelee with the North Dakota state line north of McLaughlin.
SD 44 / SD 50 in Platte 
ND 3 near Ashley 
