The 2023 Manchac Swamp Bridge Car Crash occurred on October 23, 2023, on Interstate 55 in St. John the Baptist Parish, Louisiana.

The incident was primarily caused by a combination of heavy fog and drifting smoke from nearby marsh fires, a phenomenon known as superfog.

The crash took place on the elevated section of I-55, which spans from Ponchatoula to LaPlace over the swamplands below.

During the crash, one vehicle fell into the water and partially sank, while over 100 motorists were left stranded until rescue services could reach the area.

The severe conditions and scale of the accident posed significant challenges for emergency responders.