Thomas Viaduct
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Thomas Viaduct was completed in 1835 and is the world's largest multiple arched stone railroad bridge with an arc. Enter the Avalon Area of Patapsco Valley State Park off U.S. 1 at South Street, just north of Elkridge (look for All State Plumbing at South Street). Proceed on Park Entrance Road to contact station. Thomas Viaduct is in view behind contact station. Park in driveway in front of contact station. Note Viaduct interpretive sign at contact station and carefully walk road to examine the Viaduct keeping in mind the danger of the blind curve on the roadway.