The Lake Pontchartrain Causeway, also known simply as The Causeway, is a fixed link composed of two parallel bridges crossing Lake Pontchartrain in southeastern Louisiana, United States. The longer of the two bridges is 23.83 miles (38.35 km) long. The southern terminus of the causeway is in Metairie, Louisiana, and the northern terminus is in Mandeville, Louisiana. Both are in the New Orleans metropolitan area.

A bridge is a structure built to span a physical obstacle without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it.