The British Cartographic Society

an association of individuals and organisations dedicated to exploring and developing the world of maps
http://www.cartography.org.uk/

MapHist Discussion Group

MapHist, the Map History Discussion List, is an e-mail discussion group whose primary focus is historical maps, atlases, globes and other cartographic documents.
http://www.maphist.nl/

International Map Trade Association (IMTA)

IMTA members are the companies that create and sell the maps, atlases and map-related products you use. Find information on maps, geography and mapping technology.
http://www.maptrade.org/

Ordnance Survey Britain's National Mapping Agency

Maps and mapping for Great Britain, with free mapping and services together with information on digital and paper mapping products and other aspects of cartography
http://www.ordnancesurvey.com

Washington Map Society

An informal organization of people interested in cartography, cartographic history, and collecting maps, both old and new.
http://www.washmap.org/

Australian Map Circle

The Australian Map Circle (AMC) is a national group of map producers, users and curators, which acts as a medium of communication for all those interested in maps.
http://australianmapcircle.org.au/

Mt. Diablo Surveyors Historical Society

Society of Land Surveyors interested in tne history of Mount Diablo, Northern California, and the establishment of the Mt. Diablo meridian and initial point.
http://www.mdshs.org/

North American Cartographic Information Society

NACIS is a professional society dedicated to the advancement and cooperation of all cartographic disciplines. Members include practicing cartographers, educators, map librarians, and map collectors.
http://www.nacis.org/

Ordnance Survey Ireland

The Irish national mapping agency.
http://www.osi.ie/

Society of Cartographers

Society founded in 1964 aiming to support the practising cartographer and encourage and maintain a high standard of cartographic illustration.
http://www.soc.org.uk/