The park is contiguous with a rail trail that crosses Snoqualmie Pass. The trail is located within the former right-of-way of The Milwaukee Road, officially the Chicago, Milwaukee, St. Paul and Pacific Railroad. Most of the right-of-way between Cedar Falls and the Idaho border was acquired by the state, through a quitclaim deed, as a result of the railroad's 1977 bankruptcy. As part of the reorganization of the company, the railroad embargoed its lines west of Miles City, Montana, in 1980 and ceased service in Washington. The state acquired the land in the early 1980s and eventually converted the right-of-way west of the Columbia River into a hiking, mountain biking, and horseback riding trail. The trail, known as the Palouse to Cascades State Park Trail, continues beyond Iron Horse State Park to the Idaho border. Iron Horse State Park contains the most developed portion of the trail.