The U.S. National Oceanic and Atmospheric Administration (NOAA) has over 20,000 maps of coastlines, oceans, lakes, and other waterways dating back to 1747 available free for download on the Office of Coast Survey's Historical Map & Chart Project website. The maps and charts were scanned from paper originals beginning 1995 by the Office of Coast Survey. You can search by keyword, state or region, year, and map type, including bathymetric, gravity, magnetic, and more. Two file formats are available: high-resolution JPG and SID for ArcView. A Flash-based preview allows you to examine and zoom in on each map such as in the Gulf of Mexico nautical map above. The series also contains an amazing Civil War collection that includes battlefield maps and plans of attack.