Libraries at Louisiana State University have the most complete collection of maps for the state. The Family History Library has a few historical maps, including maps of early land districts. Ward maps for New Orleans (1829, 1834, 1845, 1854, and 1898) are on FHL film 1377700 or fiche 6016695-99.
A helpful set of maps is County Parish Boundaries in Louisiana (New Orleans, Louisiana: Historical Records Survey, 1939; FHL book 976.3 E3h; film 1425651, item 5). This includes information on the laws affecting the development of the state.