The Lake Pontchartrain Causeway, or the Causeway, consists of two parallel bridges crossing Lake Pontchartrain in southern Louisiana, United States. The longer of the two bridges is 23.83 miles (38.35 km) long. Since 1969 it was listed by Guinness World Records as the longest bridge over water in the world; in 2011 in response to the opening of the longer Jiaozhou Bay Bridge in China, Guinness created two categories for bridges over water: continuous and aggregate lengths over water. Lake Pontchartrain Causeway then became the longest bridge over water while Jiaozhou Bay Bridge the longest bridge over water.
The bridges are supported by 9,500 concrete pilings. The two bridges feature bascule spans over the navigation channel 8 miles (13 km) south of the north shore. The southern terminus of the Causeway is in Metairie, Louisiana, a suburb of New Orleans. The northern terminus is at Mandeville, Louisiana.