Northern Black Hills
Eagle Cliff Trails have great cross-country skiing (groomed and ungroomed) and snowshoeing in winter with running and mountain biking in summer. Winter snow pack is probably the deepest in the Black Hills.
East of Rapid City
Badlands Trails are located east of Rapid City and offer many places to run. One of the best is the Castle Trail, which can be found by getting off I-90 at the Interior Exit. The trail starts at the first parking lot inside the park and goes west to the Fossil Exhibit. Round Trip is approximately 10 miles.
Closer to Rapid City is the Rail Road Buttes area. Many trails available here. Leave Rapid City on Hwy 44 east. Turn right (south) at the New Underwood turnoff. Rail Road Buttes is about a mile south. Please note that the 4-wheelers ignore the signs prohibiting them, and all trails are now two-track trails.