Long-Allen Bridge, K-truss bridge in Berwick, United States

The Long-Allen Bridge is a K-truss steel structure that spans the Atchafalaya River, connecting the communities of Berwick and Morgan City in Louisiana. The structure has two traffic lanes and a design that allows river vessels to pass beneath it.

Built by Ohio-based Mt. Vernon Bridge Company, it opened in 1933 and served as a crossing on the Old Spanish Trail route. The structure represented an important infrastructure development for the region in the early twentieth century.

The name links two Louisiana governors, Huey P. Long and Oscar K. Allen, though the sources do not detail the naming. The bridge carried the Old Spanish Trail and US 90 until the E. J. "Lionel" Grizzaffi Bridge opened in 1975, when through traffic shifted to the newer crossing.

Visitors can cross the bridge by car between the two communities, as it is designed for regular vehicle traffic. The crossing takes just a few minutes and offers views of the river and surrounding wetland landscape.

The bridge was built by the Mt. Vernon Bridge Co. of Mt. Vernon, Ohio, and opened in 1933. It carried the Old Spanish Trail and US 90 until the E. J. "Lionel" Grizzaffi Bridge opened in 1975. In May 2023 it closed for repairs, with reopening planned for May 2025.