Louisiana Highway 1 (LA 1) is a state highway in Louisiana. At 431.88 miles (695.04 km), it is the longest numbered highway of any class in Louisiana. It runs diagonally across the state, connecting the oil and gas fields near the island of Grand Isle with the northwest corner of the state, north of Shreveport. The part south of U.S. Highway 90 near Raceland is , a National Highway System High Priority Corridor. From Alexandria to Shreveport, the LA 1 corridor was used for Interstate 49.