The Crystal Mill, or the Old Mill is an 1892 wooden powerhouse located on an outcrop above the Crystal River in Crystal, Colorado, United States. Although called a mill, it is more correctly denoted as a compressor station, which used a water turbine to drive an air compressor. The compressed air was then used to power other machinery or tools. Today it stands as a Colorado icon. While it is often reputed to be the most photographed site in the state, this is logistically impossible, as compared to easily accessible and heavily visited Maroon Lake, near Aspen.