The southern segment begins at US 18 south-southeast of Parmelee and proceeds 20.826 miles (33.516 km) to a rural intersection just south of Norris.
Portions of SD 63 north of US 14/SD 34 west of Hayes are part of the Lewis and Clark Trail.
The portion of the highway, from just north of the intersection with SD 44 to a point approximately 5 miles (8.0 km) south of Belvidere, is a gravel road.
The southern segment of SD 63 begins at an intersection with U.S. Route 18 (US 18) south-southeast of Parmelee, in the northwestern part of both Todd County and the Rosebud Indian Reservation.
After traveling westward through Parmelee, the highway crosses over Cut Meat Creek and then skirt along the northern edge of Eagle Feather Lake.
It curves to the north-northeast and makes a stairstep pattern to the west before resuming a northward path.
At a second crossing of Black Pipe Creek, it enters the northeastern part of both Jackson County and the Pine Ridge Indian Reservation.
At a crossing of the White River, SD 63 leaves the Pine Ridge Indian Reservation.
At an intersection with D Street, the gravel road ends and the paved portion resumes.
SD 63 begins to skirt along the western edge of North Eagle Butte.
They enter the city limits of North Eagle Butte and pass some sewage disposal ponds.
The two highways travel concurrently in a due-east direction, while the roadway continue as County Road 3B (CR 3B).
It travels in a due-north direction and enters the southeastern part of both Corson County and the Standing Rock Indian Reservation.
Here, SD 63 intersects 100th Street and reaches its northern terminus, while the roadway continues as North Dakota Highway 6 (ND 6).
In the mid-1920s, a southern segment of SD 63 traveled from the Nebraska state line, south of Olsonville to Murdo.
[2] Between 1948 and 1953, the highway was realigned to begin approximately 3 miles (4.8 km) east of Firesteel.
A resolution in the 2007 legislative session urged South Dakota Department of Transportation (SDDOT) to work to connect the two segments of the highway.