I used nationalatlas.gov for many years, downloading various shapefiles regarding water, roads, boundaries, environmental factors, and more. NationalAtlas.gov was a central public site that many GIS users in the USA relied upon regularly. Nationalatlas.gov now forwards to nationalmap.gov , which has a map viewer but does not provide nearly the level of functionality or shear volume of downloadable shapefiles. So, now that nationalatlas.gov is retired, where are the largest sources of public shapefiles that can be easily accessed?