Maps and atlases have been an important part of the collections of the Library of Congress since its beginning in 1800, when a joint congressional committee purchased three maps and an atlas from a London dealer. Since then, the Library's cartographic holdings have grown to more than 5 million map sheets,105,000 atlases, 138,000 microfilm and microfiche items, 5,500 globes, 2,000 terrain models, 1.6 million aerial photographs and remote sensing images, and thousands of digital files.
The Geography and Map Division has custody of the bulk of the Library's cartographic materials. Established in 1897 as the Hall of Maps to serve Congress and federal agencies, the Geography and Map Division today functions as the National Map Library. Its primary responsibility is developing the Library's cartographic collections. An average of some seventy thousand items are acquired yearly through government deposits, transfers of superseded maps from federal libraries, copyright deposits, domestic and international exchanges, purchases, and gifts. These range from rare atlases to geospatial data, but the major focus of the Geography and Map Division acquisition program is acquiring current materials from all countries. While many of the current items are acquired through exchanges and deposits, the division relies heavily on public-spirited citizens to assist in the acquisition of rare maps and unique collections. The cartographic collections date from the fourteenth century and cover virtually every country and subject.
Maps acquired by the division since 1968 have been cataloged. As a major service to the map library community, the division establishes, maintains, and disseminates national standards for classifying and cataloging maps and atlases through the MARC (Machine Readable Cataloging) Map system.
In 1901, Philip Lee Phillips, the first chief of the Hall of Maps, reported to the Librarian of Congress that: "This collection, which is the largest extant, will in time be of great value, not only to the cartographer, but also to the historian." Due to the tireless efforts of Phillips and five generations of map librarians, the Geography and Map Division's collection of cartographic materials is of even greater value today. In addition to cartographers, geographers, and historians, the collection is heavily used by genealogists, preservationists, urban planners, ecologists, and scientists.
In an effort to reach a wider audience and to further develop, enhance, and promote the Library's geographic and cartographic collections, the Geography and Map Division established the Philip Lee Phillips Society, an association of friends of the division, in 1995.