The longest bridge in the United States is built across what lake?
The longest bridge in the United States is the Lake Pontchartrain Causeway, which spans Lake Pontchartrain in southeastern Louisiana. Connecting the cities of Metairie and Mandeville, this massive structure consists of two parallel bridges, with the longer span stretching approximately 23.87 miles (38.42 km) across the water. It is a remarkable feat of engineering that has held a place in the Guinness World Records for decades due to its incredible continuous length over the open estuary.