South Dakota Highway 25 (SD 25) is a state highway in the eastern part of the U.S. state of South Dakota. It connects Scotland, Howard, De Smet, and Webster.
It consists of two disconnected segments. Its shorter southern segment extends from SD 50 northwest of Tabor to U.S. Route 18 (US 18) west of Olivet. Its much-longer northern segment extends from SD 262 northwest of Emery, through Howard, De Smet, and Webster, to the North Dakota state line. Here, the roadway continues as North Dakota Highway 18 (ND 18).
SD 25's northern segment was established in 1926, with its southern terminus in Howard. From what is now SD 262, the SD 25 designated was applied to the road as construction occurred. Therefore, the northern terminus was at Farmer by 1971, Epiphany by 1977, and the Howard area by 1981. It was shifted west out of Howard in the early 1950s. Its northern path took a zigzag route northward. From De Smet, it went through Clark to Webster. It went west approximately and headed north to Britton. It then met the North Dakota state line northeast of Kidder. Part of this path is now SD 27. It was then shifted to its current path. In the mid-1970s, it utilized former SD 23 from Webster to Lake City. Between Hammer and the state line, it utilized part of SD 15's former path. The southern segment was the path of former SD 35. It was redesignated in 1976.
Route description
Southern segment
Bon Homme County
SD 25 begins at an intersection with SD 50 northwest of Tabor, in the southeastern part of Bon Homme County. This intersection is also the northern terminus of County Road 1A (CR 1A; 424th Avenue). SD 25 travels to the north. Between CR 30 (304th Street) and 303rd Street, it passes just west of Kubal Lake. North of 298th Street is an intersection with SD 46. South of 294th Street, it crosses over some railroad tracks of BNSF Railway. North of 293rd Street, it crosses over Dawson Creek and enters the southeastern part of Scotland. Between Washington and Juniper streets, it passes Scotland School. An intersection with Main Street leads to the business district of the city, as well as the Landmann–Jungman Memorial Hospital. An intersection with CR 2 (Dollard Street), which is signed as a truck route, leads to Lake Henry. After the highway leaves Scotland, it intersects 291st Street, where it enters the south-central part of Hutchinson County.
Hutchinson County
SD 25 curves to the north-northeast. At an intersection with CR 38 (290th Street), it curves to the north-northwest. Just south of 287th Street, it curves to the north-northeast. Just north of this intersection, the highway crosses over South Branch Lonetree Creek. Almost immediately, it curves back to the north-northwest. It curves back to the north just before meeting the northern terminus of the southern segment, an intersection with U.S. Route 18 (US 18) and the southern terminus of CR 9 (424th Avenue).
Northern segment
Hanson County
SD 25 resumes at an intersection with SD 262 and the northern terminus of CR 9 (427th Avenue) at a point northwest of Emery, in the southeastern part of Hanson County. It travels to the north. Northeast of Welker Lake is an interchange with Interstate 90 (I-90). North of 255th Street is an intersection with SD 38. It travels just to the east of Farmer. At 252nd Street, it curves to the north-northwest. At the intersection with 250th Street, it begins to curve to the north-northeast. Just south of 249th Street, the highway begins to parallel Pierre Creek. Between CR 17 (247th Street) and 246th Street, the creek ends. North of 246th Street, it passes Lutz Lake. South of CR 24 (244th Street), which leads to Epiphany, it curves to the north-northwest. At this intersection, it enters the south-central part of Miner County.