The Library of Congress has an online project of scanned maps. I have found this site to be a GREAT resource in researching original maps from the Civil War. I did a search for 'Louisiana' and posted a link here (there are more than one page, make sure to click 'next page' at the bottom).
Here are a few links for examples:
- Map of South Louisiana in 1863: Below each map you will have tools to zoom in and enlarge the size of the picture. You are able to 'copy and paste' items. Personally, I like zooming in on a map I think I can work from and 'copy and paste' multiple pieces together so I have a larger version to work from.
- Fort Burton at Butte La Rose
- Fort Jackson