Over the last few years, the United States Geological Survey (USGS) has been working to scan and process its enormous printed map collection -- of U.S. states, Puerto Rico, the Virgin Islands, and U.S. trust territories -- to make them available as free downloads in electronic format (GeoPDF).
Over the last month, the topographical maps of Louisiana became available... with New Orleans topographic coverage dating from 1891-2009.
Access via: http://nationalmap.gov/historical/index.html
Image above: Detail of "New Orleans, Louisiana" Quad 1945. Scale 1:250,000.
