Distance: 7 miles roundtrip (out and back). Elevation gain: 5,166 ft. Duration: 4-5 hours. Highest point in South Dakota. Incredible stone lookout. Great views of the black hills.
The Harney Peak Trailhead #9 is located in the northwest corner of the parking lot just beyond Sylvan Lake. From there, the hike is very straight forward – the beginning of the trail is very moderate, being slightly flat with a few ups and downs along the way.
Once you cross into the Black Elk Wilderness (don't forget to fill out the permit before moving forward), the trail descends a little more to the valley floor. On the other side of the valley, the hike intensifies for the last mile or so, heading uphill. The last quarter of a mile is mostly stairs. Once you get to the top, however, you will forget all about the climb, as you are struck by the beautiful views.
At the top of Harney Peak, if you are so inclined, you can hike quite far up on the climbing rocks.
Be sure to bring layers and rain gear with you in the summer months. The weather will change almost at the drop of a hat.