Grand Isle (French: Grande-Île) is a town in Jefferson Parish, Louisiana, United States, located on a barrier island of the same name in the Gulf of Mexico. The island is at the mouth of Barataria Bay where it meets the gulf. As of the 2010 census, the town's resident population was 1,296, down from 1,541 in 2000; during summers, the population, including tourists and seasonal residents, sometimes increases to over 20,000. Grand Isle is statistically part of the New Orleans−Metairie−Kenner Metropolitan Statistical Area, though it is not connected to New Orleans' continuous urbanized area.
Grand Isle's main street is the seaside start of Louisiana Highway 1 (LA 1), which stretches 436.2 miles (702.0 km) away to the northwest corner of the state, ending near Shreveport. LA 1's automobile causeway at the west end of the island is the only land access to or from Grand Isle.
Direct access to Grand Isle's seat of parish government is 95 miles (153 km) away in suburban Jefferson Parish.