Sweet spring water made Ash Hollow SHP near Lewellen a major stopover on the Overland Trail and prompted prehistoric Indians to use it, too. Ruts etched by west-bound wagons are visible on the bluffs at Windlass Hill. The history, archaeology and paleontology of the area are interpreted at the visitor center, Ash Hollow Cave and exhibits and structures. In 1962, the Nebraska Game and Parks Commission began acquisition of the 1,000-plus acres that now comprise the park. An interpretive center was built over the entrance of Ash Hollow Cave to protect its unique features.In 1978, the Nebraska Game and Parks Commission opened the visitor center on the bluff overlooking the mouth of the canyon. A hiking trail from the visitor center provides access to the spring in the bottom of the canyon. Also a part of the park, Windlass Hill is located on a separate tract 2 1/4 miles south on U.S. 26. Development there includes an interpretative shelter and informal signs. A walkway provides access to the crest of the hill to view the deep ruts carved by those thousands upon thousands of wagons that traveled the trail those many decades ago.