Pass Manchac Light, Lighthouse site in Tangipahoa Parish, Louisiana, United States

Pass Manchac Light was a brick cylinder with an attached one-and-a-half-story keeper's house, built in 1857 on the north side of the pass between Lake Pontchartrain and Lake Maurepas. The tower and dwelling were joined at the same height, a design not repeated elsewhere on the Gulf Coast.

The first lighthouse here was built in 1838 after Congress approved it on March 3, 1837, to mark the link between Lake Pontchartrain and Lake Maurepas. Three towers followed in 1842, 1846 and 1857, each replacing one lost to poor construction or rising lake water. The 1857 brick tower served until 1987, when the Coast Guard replaced it with a skeleton tower on the south side of the pass.

The station's fourth tower, finished in 1857, was a brick cylinder joined to a one-and-a-half-storey brick dwelling, the only tower of that form built on the Gulf coast. The keeper's house was removed in 1952 once the light stood on an island rather than a peninsula. The lantern room, taken off the tower in 2002 for restoration, has been displayed at the Lake Pontchartrain Basin Maritime Museum in Madisonville since February 2008.

Access to the former site is possible from the water, since the remains stand in a lake. The lantern room that held the main light is now kept at a nearby museum and can be viewed there.

A major hurricane destroyed the structure completely, leading to its removal from the official registry of historic places. What remains of the building is mainly remembered through its purpose and the preserved components now held in a museum.