The Ryan House and Lost Horse Well is a historic district in Joshua Tree National Park, California, United States. It was established by the Ryan family, the later developers of the Lost Horse Mine, which became the most profitable mine in the area. The Lost Horse Well at the Ryan Ranch supplied water to the Lost Horse Mine, 3 miles south and 750' higher, by pipeline.
The six-room house was built as an adobe residence in 1896 with later wood frame additions. It was destroyed by fire August 12, 1978. Originally roughly 30 feet by 40 feet, the ruin has 3 rooms, each measuring 12 feet wide and 16 feet long. Adobe walls sit on stone masonry foundation and there are concrete stoops on the north and south sides. There is a small stone fireplace located on the east side of the house.