Castle Ruins Falls is a 30-foot waterfall on Glacial Boulder Creek in Park County, Wyoming, in the Middle Rockies region. It lies about 31.6 miles east of West Yellowstone and roughly 116.7 miles northeast of Idaho Falls as the crow flies.
At 30 feet it is on the modest side for Wyoming, where the typical waterfall with a recorded height stands around 60 feet; it ranks 157th of 230. By form it is a plunge, where the water drops vertically and loses contact with the rock face.
The Middle Rockies are high, glaciated mountain ranges with alpine peaks, subalpine fir and spruce forest, lodgepole pine and grassy intermontane valleys. Snowmelt streams cascade down glacial valleys and canyon walls.
Park County holds 114 recorded waterfalls, and several are close by. Silver Cord Cascade, a 1,200-foot tiered waterfall, is under a mile away. Red Rock Cascade, a 260-foot slide waterfall, is about 1.1 miles away. Lower Yellowstone Falls, a 308-foot plunge waterfall, is about 1.5 miles away.
Castle Ruins Falls is located at 44.7268° N, 110.4681° W. The listing is based on the World Waterfall Database, one of the sources compiled by the U.S. Geological Survey in its inventory of waterfalls and rapids of the conterminous United States. The position was verified on aerial imagery. Details on trails, parking and access have not been documented for this waterfall yet.