From The Castle Rock Museum & Historical Society: (visit link
The Castle Rock Museum is housed in a structure which by any account is its prime artifact. The Denver & Rio Grande Railroad had just been built between Denver and Old Colorado City (Colorado Springs) in 1871. It was the first narrow gauge line in the United States and its builder, General William Jackson Palmer, had selected several communities along its route as deserving of rail sidings or depots. Castle Rock was not one of them until 1874 when it was designated as county seat of the newly re-aligned Douglas County.
By 1875 a trim small depot was erected on third street in the bustling new village of Castle Rock. It was constructed of Rhyolite building stone native to the area around Castle Rock and designed in the style of the period with wide eaves supported by drop-pendant brackets. The stone work was finely detailed on corners or building edges or around sills and lintels.
Although the Depot was moved from trackside to its present location in 1970, it was carefully restored by the Castle Rock Historical Society in 1996 for use as a local history museum. The building still retains the original interior features such as the old ticket window and baggage area with 125 years of graffiti on its walls.
The Denver and Rio Grande Depot was placed on the National Register of Historic Places in 1974 and the Castle Rock Register of Local Landmarks in 1994.
Video Tour of the Museum: (visit link