The alphamegalog of the cities of Louisiana lists the largest city in Louisiana for each letter of the alphabet. In this case, ‘largest’ is based on population within the city proper.

Alexandria
Baton Rouge
Central
DeRidder
Estelle
Franklin
Gretna
Houma
Inniswold
Jennings
Kenner
Lafayette
Monroe
New Orleans
Opelousas
Prairieville
Quitman
Ruston
Shreveport
Terrytown
Urania
Ville Platte
West Monroe
(no X)
Youngsville
Zachary