Located on the Fremont National Forest on the east side of the Cascades in central Oregon, Horse Fly Mountain has two summits. The original lookout was located on the southern point. It was constructed of sawn timbers and boards. In 1934 the first tower on the northern point was constructed, an L-4 on a trestle type tower. In 1961 it was replaced with the current R-6 flattop cab with catwalk on a 41' treated timber tower. Placed on standby status in the 1970s, the lookout has been reactivated and staffed in recent years.