The National Geologic Map Database (NGMDB) includes a suite of databases and standards widely used to support scientific researchers, as well as decisionmakers, the private sector, and the general public. The NGMDB is a collaborative activity managed by the Association of American State Geologists (AASG) and the U.S. Geological Survey. This partnership serves to advance both the goal of building the NGMDB and the need for each geological survey to improve their ability to deliver digital and analog map information to their users. Justification for the NGMDB is provided by the Geologic Mapping Act of 1992 and its subsequent reauthorizations, which mandates its development and the standards necessary to support its implementation. The NGMDB provides access to geoscience maps and associated information, including: 1) various Web-accessible databases (e.g., a Map Catalog of bibliographic information about geoscience maps, a geologic names lexicon, a prototype Paleontology database, and a prototype Image Library of geologic maps); 2) a comprehensive standards-development effort in collaboration with the North American Data Model Steering Committee (including the design and testing of the requisite conceptual and physical data model, and development of a standard science language for describing geologic features); and 3) development of a prototype, online map database. Information and links to the databases are available at http://ncgmp.usgs.gov/ngmdbproject/.