The Riddle Ranch is a pioneer ranch complex in Harney County in eastern Oregon, United States. The ranch is located on both sides of the Little Blitzen River on public land administered by the Bureau of Land Management. The original ranch buildings were constructed by three brothers, Benjamin, Frederick, and Walter Riddle. In the 1950s, the ranch was sold to Rex Clemens. The Bureau of Land Management bought the ranch in 1986. Today, the ranch is maintained as an open-air museum with original artifact displayed where they were used. Visitors can explore the ranch buildings, hike, or fish; however, camping is not permitted. There are a number of Native American archeological sites on the ranch property. These sites are not open to the public. The Riddle Ranch is listed as a historic district