Overseas Highway and Railway Bridges (Boundary Increase)

The story

Written by AI from this property's National Register nomination and the record above; every sentence is checked against its sources before it appears here. Corrections: privacy@treealive.com

The Overseas Highway and Railway Bridges (Boundary Increase) is a historic district of bridges running parallel to US 1 near Key Largo in Monroe County. Its twenty contributing bridge structures were built mainly from 1906 to 1912, during construction of the Key West Extension railway.

Why it's listed

It was listed in the National Register in 2004 under criteria A and C, with significance in transportation and engineering at the national, state and local levels. Its period of significance runs from 1906 to 1954, anchored by the railway bridges' construction between 1906 and 1912.

Physical character

The bridges combine steel plate girder spans, concrete arches and steel trusses, including one swing truss drawbridge. Roadways carry a 12-inch concrete deck under a bituminous wearing surface, set on concrete foundations and steel framing, across 20 miles of fill embankments and 17 miles of bridges.

Historical context

Henry Flagler announced the Key West Extension project in 1905, and William Krome and Joseph Meredith served as its engineers. The first train reached Key Largo in 1907, and reached Knight's Key Dock at Marathon in 1908. A 1910 hurricane claimed two lives, and the railroad went bankrupt in 1932. The 1935 hurricane threatened the work camps, and the railroad became the Overseas Highway for automobile traffic between 1938 and 1944. The original bridges were eliminated from 1978 to 1983 after a new highway opened parallel to the old road in the 1980s.