[1]South Dakota Highway 9 was a short state route in Marshall County.

It was one of only two known single digit state highway numbers used in South Dakota.

When initially established in the mid-1920s, the western terminus of South Dakota 24 was at Whitewood, west of Sturgis.

It traveled east along what is now South Dakota Highway 34 to near Marcus, then northward to Faith.

This northward segment was shifted east around 1931, to what is now South Dakota Highway 73; it became part of the latter's alignment in 1936.

A branch of SD 24, called South Dakota Highway 24A, extended northwest from Whitewood to Belle Fourche.

A further extension was made in the early 1950s west from Belle Fourche to the Wyoming border.

When assigned in the mid-1920s, SD 41 ran nearly the entire length of the state north to south.

When U.S. 281 was assigned in the early 1930s, it was routed along the SD 41 alignment between the North Dakota border and U.S. 14.

Around 1936, the dual signage was dropped, and the northern terminus of SD 41 was located at Plankinton.

No changes took place in the 1940s, however, in the early 1950s, another alignment change in U.S. 281 took over the remainder of SD 41, and the number was discontinued.South Dakota Highway 54 was a short state route in southeast Gregory County, South Dakota.

Around 1953, due to the pending flooding of its old alignment, U.S. 18 was rerouted south onto this route, and SD 54 was limited to a 1-mile (1.6 km) segment north of the border.

The road became part of U.S. Highway 83 in the 1940s, when the alignments of U.S. 83 and U.S. 183 were swapped.South Dakota State Highway 298 served the former Black Hills Ordnance Depot at Igloo, in far southwest South Dakota (Fall River County).