Cassiobridge was a proposed London Underground station in Watford, Hertfordshire, England. The station would have been part of the Croxley Rail Link project, a scheme to extend the Metropolitan line to Watford Junction railway station. It would have been served by Metropolitan line trains between Watford Junction and Central London via Baker Street. The railway line would run over Ascot Road via a viaduct and the platforms would have been situated on the east side of the road. Entrance to the station would have been from the west side of the road, with a ticket hall and other facilities at street level. Passengers would gain access to the platforms via stairs and lifts and a short footbridge over the road.