Collections of physical samples and data managed and preserved by the U.S. Geological Survey (USGS). The separate collections are managed by different projects and Mission Areas of the USGS. The collections are distributed across the United States, in various USGS offices. Preservation of some of these collections may be supported by the National Geological and Geophysical Data Preservation Program. USGS strives to publicly expose its materials, data, and other research to further scientific inquiry. Points of contact for individual collections may be contacted to request access to materials and data.