Service Alert
Hege Library & Learning Technologies
List via http://gisgeography.com/free-gis-software/
The National Map Viewer
TopoView
Historical Topographic Map Collection
National Geologic Map Database
USGS Mineral Resources
Mineral Resources Data System (MRDS)
National Minerals Information Center
Mineral Commodity Summaries (2017)
USGS Science Data Catalog
USGS Publications Warehouse