The Galveston Causeway is a set of causeways in Galveston, Texas, United States. Two of the routes carry the southbound and northbound traffic of Interstate 45, while the original causeway is restricted to rail traffic. It is the only free roadway access point to Galveston Island. The causeway carries traffic over Galveston Bay and the Gulf Intracoastal Waterway. The original causeway was built in 1912 and carried both rail and auto traffic. The auto traffic was transferred to new causeways built to the west in 1939, leaving the original bridge for rail traffic.