Redstone is a census-designated place in Pitkin County, Colorado, United States. The population as of the 2010 Census was 130. The U.S. Post Office at Carbondale (ZIP Code 81623) now serves Redstone postal addresses. The village is listed on the National Register of Historic Places as an historic district and includes several properties that are also separately listed on the National Register.
Redstone was established in the late 19th century industrialist John Cleveland Osgood as part of a coal mining enterprise. Osgood's coal empire also spurred construction of the Crystal River Railroad and Redstone's historic dwellings. As an experiment in "enlightened paternalism," Osgood constructed 84 cottages and a 40-room inn, all with indoor plumbing and electricity, for his coal miners and cokers, as well as modern bathhouse facilities, a club house with a library and a theatre, and a school. Most of these Craftsman-era Swiss-style cottages are still used as homes.
A dominant feature of Redstone is Cleveholm Manor, commonly called "Redstone Castle," an opulent 42-room Tudor-style mansion that Osgood built for his second wife, Swedish Countess Alma Regina Shelgrem. Construction of Cleveholm Manor, which was designed by New York architects Boal and Harnois, began in 1897 and was completed in 1901. The Castle was part of a 72-acre (29 ha) that also included servants' quarters, a gamekeeper's lodge, a carriage house, and a greenhouse. Cleveholm Manor and the gamekeeper's cottage are both independently listed on the National Register as Osgood Castle and Osgood Gamekeeper's Lodge, respectively. As of 2004, the Castle still contained 75 percent of its original furnishings.