At one time, LA 23 ran straight across the
Westbank Expressway (
U.S. Highway 90 Business), using Lafayette Street, 5th Street and Huey P. Long Avenue through downtown Gretna and crossing the
Jackson Avenue-Gretna Ferry onto
Jackson Avenue in New Orleans. By 1986, it had been rerouted, running along the Westbank Expressway
frontage roads to Stumpf Boulevard and turning north on Stumpf and Franklin Avenue to end at Burmaster Street (
LA 428). The former LA 23 to 4th Street in downtown Gretna became an extension of
LA 18, while the three blocks beyond to the ferry (and Jackson Avenue in New Orleans) are now unnumbered. Before the 1950s, LA 23 went through Terrytown via present-day Behrman Highway (
LA 428). Twinning of the highway in Plaquemines Parish was begun by
Judge Perez in the 1960s. The vertical lift bridge in Belle Chasse was added in 1968, and the Empire Jetty Bridge over Dollut Canal, a high-rise bridge, opened in 1976, replacing a 26-year-old lift bridge. In Plaquemines Parish, sections of the original LA 23, since bypassed, are signed as Parish Road 11 (although some maps erroneously list these routes as LA-11), such as in Jesuit Bend and the area south of Port Sulphur through Empire, Buras, and Fort Jackson. Prior to Louisiana's 1955 highway renumbering, LA 23 through Plaquemines Parish was LA 31, and there are some bridges, such as the Bayou Barriere crossings in northern Belle Chasse, that still bear the original numbering. As of 2019, the portion from U.S. Highway 90 Business to LA 428 is under agreement to be removed from the state highway system and transferred to local control. Before 2025, in Belle Chasse, the highway crossed the
Gulf Intracoastal Waterway via two antiquated crossings: southbound traffic used the 1955-vintage
Belle Chasse Tunnel, a narrow crossing that does not allow passing; northbound traffic used the 1967-vintage
Judge Perez Bridge, a
vertical-lift bridge. Both were replaced by the new tolled
Belle Chasse Bridge, which opened for southbound traffic on December 20, 2023, and northbound traffic on March 17, 2025. ==Major intersections==