Osgood Castle, also known as Cleveholm or Redstone Castle, is a mansion south of Redstone, Colorado, United States. It is a large timber frame structure built in the early 20th century as the home of John C. Osgood, founder of the Colorado Fuel and Iron Company, in a simplified version of the Stick style. In 1971 it was added to the National Register of Historic Places, the first property in Pitkin County to be listed.