In Spearfish Canyon, you get to travel along the course of a stream, and marvel as you look up at the tall canyon wall, which can get to be over 1000 feet high in some places. The canyon's also home to some really beautiful waterfalls! Plus, the area is really easy to get to, and easy to explore.
Moving on down the road, there are two more waterfalls that are worth a stop. About 15 miles south of Spearfish is a three-way intersection where you'll find a lodge and a restaurant. Park in the little parking lot to the right of the Latchstring Restaurant to access the first of these two waterfalls. The falls aren't well-marked, so look for the restaurant's sign.
You can actually hear the falls from the parking lot, and if you go to the far right end of the lot, you'll be standing beside the very top of the falls. There are a lot of trees and brush in the way, and the shape of the cliff prevents you from seeing the rest of the drop, but you can see the point where the water tumbles over the cliff, and appreciate how high you are over Spearfish Creek below.
I chose to drive. Like the rest of the canyon, there are numerous places to pull over and enjoy the view, which gets even better here. In many places, the stream is covered with a carpet of aquatic plants, which give it an almost mystical feel.
The parking lot is just above the falls, and there are viewing platforms on both sides of the stream to view the falls from the top of the surrounding cliffs.