The original structure, Union Depot, was built in 1881 and later destroyed by fire in 1894. The second station was rebuilt in Beaux-Arts style. Each of the first two structures included clock towers. In 1914 the station's central building was demolished and rebuilt to keep up with increase traffic at the time. During its heyday, it was served by 80 daily trains operated by six different railroads. Today it still serves passenger traffic, including:
- Amtrak's California Zephyr
- Denver & Rio Grande Western Railroad's Ski Train, between Denver and the Winter Park Ski Resort.
- C Line and E Line light rail routes.
No architect is credited in any of the official information on the station.
- Denver Union Station
- Denver Union Station (USA RailGuide -- TrainWeb)
- Ski Train (includes Flash content on home page which makes sound; however site is fully usable without Flash)
- Platte Valley & Western HO Scale Model Railroad in the Basement of the station - open Friday Nights 7pm to 9pm
- Friends of Union Station