Iron Horse State Park, part of the Washington State Park System, is a 1,612-acre (7 km2) state park located in the Cascade Mountains and Yakima River Valley, between Cedar Falls on the west and the Columbia River on the east.
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, MT 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 110 miles (177 km) of hiking, mountain biking, and horseback riding trail. The trail, known as the John Wayne Pioneer Trail, continues beyond Iron Horse State Park to the Idaho border. Iron Horse State Park contains the most developed portion of the trail.
At Cedar Falls, the west end of Iron Horse State Park, the John Wayne Pioneer Trail connects to the Snoqualmie Valley Trail of the King County Regional Trail System. The Snoqualmie Valley Trail is built on a portion of the former Milwaukee Road branch line from Cedar Falls to Everett.
Like most rails-to-trails projects, Iron Horse is popular with hikers and cyclists. There are many trail heads across the state, most with modern facilities, ample parking for a less common trail, and even a handful of campgrounds.