Nelson Ranch Open Space and Trail is accessible from the Sharptail Open Space and Trail at Roxborough Park Road, and is located behind the hogback, south of Roxborough State Park, this open space protects a variety of wildlife habitats.
The Swallowtail trail loops are hidden behind the uplifted hogback formations of the Front Range on Douglas County’s Nelson Ranch Open Space. The loops wind among rocks and ledges, through shrublands speckled with pines and firs, and over intermittent creeks and upland meadows.