Castle Trail is a 10.7 mile lightly trafficked loop trail located near Interior, SD that features beautiful wild flowers and is rated as moderate. The trail is primarily used for hiking, walking, nature trips, and birding and is accessible from April until October.
This is a largely flat trail with spectacular views. You may see some big horn sheep. The bighorn sheep seem to be more active in the early afternoon. It is possible to extend the hike through some short out and back trails along the way.
Hiked this trail - along with Medicine Loop - in mid summer sun with temperatures near 100. This was a magnificent hike - walking through towering the badlands formations became hypnotic, like walking through a cathedral where one feels the need to remain reverently quiet. Just stunning. The flat terrain means that even the long distance in the heat was not very difficult. Sunscreen, sunglasses, and hat recommended.
Did the Castle Trail / medicine root loop. Nice views and flat, but hot. Paranoid about rattlers but didn't see any. Hot. No water at trailhead; pit toilet. Crowded at parking lot but trail is empty.
Incredible views. Best to hike early in the morning before it gets too hot.
It was a tough trail when the tempature was closing on 90, as it is all exposed edge-of-grassland hiking with no shade. My wife and I shared around 11 liters of water to get through to the end of this out and back trail. But the Badland views made it worth the effort.
This trail was a moderate to easy trail. It takes you through some great scenery. It is by far one of the most interesting trails in the park. We did it in two stages. One using the Saddle Pass trail as the access and exit and the other using Medicine Root and making it a loop.