Size, of course, is not necessarily the most important consideration. Praise should be given to those sites with high resolution images - i.e. those of research quality, in which every name is clearly legible - organised around a coherent theme, and properly referenced. Happily, many of those in this summary listing meet those requirements. See also a note about 'Innovative' sites.

Some of the sites, such as the Library of Congress's 'American Memory' or David Rumsey's privately sponsored Collection, are deservedly well known. Others of comparable size are not. Of note are the large numbers of high quality images on, for example, the New South Wales 'Parish Map' site (35,000), and the 85,000 19th century plans of Great Britain available via the Landmark/Ordnance Survey site.

The sites are given in the order they appear in this listing and linked to the relevant page or section. NB. Many are still being developed and the totals given may be out of date.

General Sites
• Amsterdam University Library ’Kaartencollectie’(Large general sites - about 2000(?), very high res.)
• Berkeley. University of California, Berkeley, Earth Sciences & Map Library (Large general sites - several hundred, high res.)
• Bibliothèque nationale de France (Large general sites - several thousand, very high res.)
• Boston Public Library (Large general sites - over 2,200, high res.)
• British Library 'Online Gallery' (Large general sites - over 5000 (?), medium res.)
• Broer Map Library (Large general sites - 3,450, high res. )
• 'Cartographic Images', from Jim Siebold (Large general sites - about 1,400, low res.)
• David Rumsey Collection (Large general sites - 20,042, high res.)
• 'Europeana' (Large general sites - 11,540, medium res.)
• 'GEOWEB', Biblioteca Nazionale Marciana, Venice (Large general sites - about 26,000, low res.)
• 'Harvard University' (Large general sites - apparently several thousand, high res.)
• 'Historic Map Works' (Large general sites - over 225,000, high res. [incorporating 3,941 from the Osher Map Library, University of Southern Maine])
• Library of Congress, 'Map Collections: 1500-1999' (Large general sites - 12,000 [in 'American Memory' - others elsewhere, though not necessarily high res.], high res.)
• Map Library of Catalonia (Large general sites - 5,000, high res.)
• Marco Capurro (Large general sites - 1,200 (?), low res.)
• Memory of the Netherlands Project (‘Het Geheugen van Nederland’) (Large general sites - high res. images)
• National Library of Australia (Large general sites - evidently many thousands, very high res.)
• National Maritime Museum (Large general sites - nearly 2,000, high res.)
• Netherlands, National Archives (Large general sites - 1,786 very high res.)
• New York Public Library. 'NYPL Digital Gallery' (Large general sites - 6,901, medium res., enlargeable with plug-in)
• Perry-Castañeda Library Map Collection, the University of Texas at Austin. 'Historical Maps' (Large general sites - about 3,500 [pre-1950], high res.)
• Royal Tropical Institute, Amsterdam [Het Koninklijk instituut voor de Tropen (KIT)]) (Large general sites - 11,500, high res.)
• Roy V. Boswell Collection (Large general sites - 1,500, high res. details)
• Rucker Agee Map Collection (Large general sites - 687, high res.)
• Ryhiner Collection (Large general sites - 16,428, high res.)
• Soviet maps (Large general sites - 30,719)
• Stuckenberg Map Collection (Large general sites - over 500, very high res.)
• University of Alabama 'Historical Map Archive' (Large general sites - over 28,000, high res. [from different collections])
• University of Michigan Library. 'Miscellaneous - a handful of maps' (Large general sites - 1,070, very high res.)
• Visual Collections: Images of Art, History and Culture (Large general sites - over 15,000, high res.)
• World Digital Library (Large general sites - 306, high res.)
• (Larger map dealer sites [some of which carry hundreds, or even thousands of map images for all parts of the world, arranged geographically, e.g. Art Source International's 12,625 maps, and Barry Lawrence Ruderman's 4,000; some are noted as being high res.])

Themes
• ‘Atlas Coelestis’ (Themes - ‘Celestial’: 32 atlases, medium res.)
• Road map covers (Themes - 'Road maps': over 1000, medium res.)
• Urban. Dutch town books (Themes - 'Stedenatlassen': about 1,200, very high res.)

World atlases

• German atlases (World atlases - over 3000, medium or high res.)
• Atlas Van Loon (World atlases - many hundreds, high res.)
• Blaeu. Toonneel des Aerdrycks, ofte Nieuwe Atlas (World atlases - 6 volumes, high res.)
• 'Frederik V's Atlas' (World atlases - (?) over 3000, high res.)
• Johannes van Keulen Zee-Fakkel (World atlases - 571, high res.)

Africa

• ‘Afriterra Maps Catalog’ (Africa - over 500, very high res.)
• 'L'Europe découvre l'Afrique' (Africa - about 800, very high res.)
• 'Maps of Africa', Stanford University (Africa - 578, high res.)

America (general)

• 'The Archive of Early American Images' (JCB) (American Continent (general) - 774, very high res.)

  North America (general)

• 'Historical Maps Online' (North America - 409, high res.)

  Canada

• ArchiviaNet (Canada - about 1,500, high res. )
• Early Maps of Newfoundland and Labrador (Canada - about 380, medium res.)
• 'MIRAGE. Map Image Rendering DAtabase for GEoscience' (Canada - over 10,000, high res. )
• Nouvelle-France: Horizons Nouveaux (Canada - between 240 and 1,000 [resolution not known])
• Bibliothèque et Archives nationale Québec (Canada - Québec: 'thousands', very high res.)

United States

• 'American Shores: Maps of the Middle Atlantic Region to 1850' (United States (general) - initially about 750, medium and high res.)
• NOAA (United States (general) - 'Image Catalog': over 21,000, high res.)
• 'United States Topographic Maps 1:250,000' (United States (general) - a large collection, high res.)
• NOAA - 'Civil War' (United States (people & themes) - 394, high res.)
• 'Zazzle Special Collections' (United States (people & themes) - 1,600, medium res.)
• USGenWeb (United States (states & regions) - see beginning of the section)
• University of Alabama. 'Fire Insurance Maps' (United States (states & regions) - Alabama: 3,121, high res.)
• University of Alabama, 'Historical Map Archive' (United States (states & regions) - Alabama: about 7,000, high res.)
• 'Rare Map Collection Gallery' (United States (states & regions) - Alaska: 713, high res.)
• 'Guide to the maps of private land grant cases of California' (United States (states & regions) - California: about 1,450, high res.)
• ’Union Map Catalog’ - California (United States (states & regions) - California: 3,761, low to medium res.)
• University of California. 'Calisphere' (United States (states & regions) - California: 2,294, high res.)
• Works Progress Administration (WPA), Digital Archive (United States (states & regions) - California: 345, high res.)
• 'Building Colorado Story by Story: the Sanborn Fire Insurance Map Collection' (United States (states & regions) - Colorado: 346 maps on 2,385 sheets, high res.)
• University of Connecticut's MAGIC site (United States (states & regions) - Connecticut: large selection, high res.)
• Florida Center for Instructional Technology, 'Exploring Florida' (United States (states & regions) - Florida: over 3,100, high res.)
• 'Sanborn Fire Insurance Company maps of Florida' (United States (states & regions) - Florida: 3,000, high res.)
• 'Visual Collections. World Map Collection' (United States (states & regions) - Florida: 4,563, high res.)
• Digital Library of Georgia (United States (states & regions) - Georgia: 4,445, very high res. )
• Hargrett Library (United States (states & regions) - Georgia: over 1000, high res. [covering America in all its aspects])
• 'Federal Township Plats of Illinois (1804-1891)' (United States (states & regions) - Illinois: 3,457, high res.)
• 'Historical Maps Online' (United States (states & regions) - Illinois: 417, high res.)
• 'Indianapolis Sanborn Map and Baist Atlas Collection' (United States (states & regions) - Indiana: 1,041, very high res.)
• Digitized Kansas Maps (United States (states & regions) - Kansas: over 325, very high res.)
• ‘LOUISiana Digital Library’ (United States (states & regions) - Louisiana : 500, very high res.)
• Lousiana State Museum Map Database (United States (states & regions) - Louisiana: about 700, fairly high res.)
• Louisiana State University Digital Library (United States (states & regions) - Louisiana: 512, high res.)
• 'Minnesota Maps Online' (United States (states & regions) - Minnesota: over 3,600, high res.)
• Kansas City, Local History collection (United States (states & regions) - Missouri: 697, low res.)
• 'Sanborn Maps for Missouri' (United States (states & regions) - Missouri: 6,798, very high res.)
• Plats of Nevada State Lands (United States (states & regions) - Nevada: over 4,200, high res.)
• 'Historic Map Works' (United States (states & regions) - New England: a large, growing collection, high res.)
• University of New Hampshire, USGS maps of New England and New York (United States (states & regions) - New England: over 1,500, very high res.)
• 'New York City Fire Insurance Atlases' (United States (states & regions) - New York City: 2,700, high res. )
• 'North Carolina Maps' (United States (states & regions) - North Carolina: 766, very high res. )
• Oklahoma Historical Society (United States (states & regions) - Oklahoma: over 600)
• 'PhillyHistory.org' (United States (states & regions) - Pennsylvania - Philadelphia: 5,003, medium res.)
• ‘Historic Pittsburgh' (United States (states & regions) - Pennsylvania - Pittsburgh: over 1,300, high res.)
• University of Pittsburgh (United States (states & regions) - Pennsylvania - Pittsburgh: 668, high res.)
• 'Sanborn Fire Insurance Maps of South Carolina' (United States (states & regions) - South Carolina: over 800, high res.)
• 'Maps of Dallas County' (United States (states & regions) - Texas: about 3,500, high res.)
• Texas General Land Office Map Collection (United States (states & regions) - Texas: [an unknown number of the 17,000 images are maps, low res.])
• Texas State Archives (United States (states & regions) - Texas: about 700 (?), high res.)
• University of Washington Libraries (United States (states & regions) - Washington State: 857 (not all maps), medium res.)
• Washington State University (United States (states & regions) - Washington State: 1,010, medium to high res.)
• Stanford Geological Survey (United States (states & regions) - West: 488, high res.)

South & Central America, and West Indies


• Brazil. 'Biblioteca Virtual da Cartografia Histórica' (Mexico, Central & South America and the West Indies: apparently 1,517, very high res.)
• Latin America. 'Biblioteca Digital Hispánica. Mapas de América' (Mexico, Central & South America and the West Indies: 527, medium res.)
• Surinam and Guiana (Mexico, Central & South America and the West Indies: over 400, medium res.)

Asia


• 'Atlas Mutual Heritage' (Asia - East Indies: c. 473 MS maps and drawings, high res.)
• Nationaal Archief 'Kaarten van de VOC' (Asia - East Indies: 469, very high res.)
• 'Ancient maps of Jerusalem' (Asia - Holy Land: over 400, high res.)
• 'Holy Land Maps' (Asia - Holy Land: about 1,100, high res.)
• Japanese Historical Map Collection (Asia - Japan: about 2,300, high res.)
• Kano Collection (Asia - Japan: about 450, medium or high res.)

Australia


• Auckland City Libraries. 'Maps Online' (Australia & Oceania - New Zealand: over 1000, high res.)
• 'Maps of Australia' (Australia & Oceania - (about 4,000 [though many are modern]), high res.)
• National Library of Australia (Australia & Oceania - (nearly 7,000, high res.)
• New South Wales Department of Information Technology and Management, 'Parish Map Preservation Project' (Australia & Oceania - 35,000, high res.)

  Europe

  CONTINENTAL EUROPE
  

• Historic Cities Center, Hebrew University of Jerusalem, and the Jewish National and University Library, 'Historic Cities' (Continental Europe - Town Plans: over 500, very high res. - see Oddens' Bookmarks for links to the separate sheets) [though note that this site is no longer being maintained]
• Ministère wallon de l'Equipement et des Transports. 'Patrimoine Cartographique de Wallonie' (Continental Europe - Belgium: 15,454 cartographic documents of various types, high res.)
• 'Stare karte Hrvatske' (Continental Europe - Croatia: 563, medium res.)
• 'Císarské povinné otisky stabilního katastru Cech' (Continental Europe - Czech Republic: over 8,000, high res.)
• Finnish estate plans (Continental Europe - Finland '1600-luvun maakirjakartat': several hundred, high res.)
• Kymenlaakson historialliset kartat [KYHIKA] (Continental Europe - Finland: over 1000, low res.)
• France [see first entry, 'Patrimoine numérique'] (Continental Europe - France: linking to archive sites, with many thousands of scans)
• 'Coin des Cartes Anciennes' (Continental Europe - France: several hundred, medium to high res.)
• 'Expériences de terrain et compétences cartographiques' (Continental Europe - France: about 800)
• 'Histocarto' (Continental Europe - France: 4,147 (most with images))
• Plans cadastraux des Côtes d'Armor (Continental Europe - France: about 6,400, high res.)
• Plans cadastraux: Mayenne (Continental Europe - France: several thousand, high res.)
• Images anciennes d'Orléans (Continental Europe - France: about 400, very high res.)
• Deutsche Kolonialgesellschaft Bibliothek (Continental Europe - Germany: over 500, low res.)
• Landkartenarchiv (Continental Europe - Germany: 360, high res.)
• 'Ortsblätter des 19. Jahrhunderts Bayerns Städte und Dörfer' (Continental Europe - Germany: 2,400, high res.)
• 'Kartenforum Sachsen' (Continental Europe - Germany: over 600, high res.)
• Samourka Map Collection (Continental Europe - Greece: c. 1,200, low-medium res.)
• 'Maps and Images' (Continental Europe - Italy (atlases): about 350, high res.)
• e-Geo: un mare di carte (Continental Europe - Italy (geology): 3,100, very high res.)
• 'Atlante storico iconografico delle città toscane' (Continental Europe - Italy (towns): 564, high res.)
• Rome, Archivio di Stato (Continental Europe - Italy - Rome: "about 5,000 digital colour photos of maps and manuscripts, 25,000 colour scans of ancient maps and parchments, 100,000 greyscale scans of cadastre and notarial registers", high res.)
• Turin, Archivio di Corte (Continental Europe - Italy - Turin: 4,538 [of 6,500], high res.)
• Beeldbank (Continental Europe - Netherlands: 418, medium res.)
• Bodel Nijenhuis Collection (Continental Europe - Netherlands: 585, high res.)
• 'Wat Was Waar' (Continental Europe - Netherlands: 18,467, high res.)
• 'Gemeente Atlas van Nederland. J. Kuyper 1865-1870' (Continental Europe - Netherlands: up to 1000[?], high res.)
• Nationaal Archief (Continental Europe - Netherlands: 1,786 enlargeable thumbnails)
• 'Brabant in Kaart' (Continental Europe - Netherlands: 623, very high res.)
• 'Noord-Hollandse Beeldbank' (Continental Europe - Netherlands: 604 large thumbnails)
• 'Overijssel in Kaart: De geschiedenis van Overijssel in oude en nieuwe kaarten' (Continental Europe - Netherlands: 431, high res.)
• Biblioteca Nacional, Portugal (Continental Europe - Portugal: 324, high res.)
• Projeto SidCARTA (Continental Europe - Portugal: perhaps over 10,000, low to medium res.)
• James Ford Bell Library's Russian selection (Continental Europe - Russia: large selection, medium res.)
• 'Digital National library of Serbia' (Continental Europe - Serbia: about 950(?), medium res.)
• Madrid, Biblioteca Nacional (Continental Europe - Spain: apparently 1,629, enlargeable)
• 'Biblioteca Digital Hispánica' (Continental Europe - Spain: a large number, medium res.)
• Lantmäteriverket. 'Historical Maps' (Continental Europe - Sweden: over 100,000 [with a target of 300,000 for the end of 2002], high res.)
• Ryhiner Collection (Continental Europe - Switzerland: about 1000, medium res.)
• Siegfriedkarte (Continental Europe - Switzerland: about 4,080, low to medium res.)
• Zentralbibliothek Zürich (Continental Europe - Switzerland: 1, 014, high res.)

BRITISH ISLES


• British Library's 'Online Gallery' (British Isles), comprising:
  ’King George III Topographical Collection’ (British Isles: about 3,000, medium res.)
  Ordnance Surveyors' Drawings (1780s-1840s) (British Isles: 351, low to medium res.)
  ‘The unveiling of Britain’ (British Isles: 815 maps and views, medium res.)
  Crace Collection of London Plans (British Isles - England - London: 1,200, medium res.)
  
• 'e-Mapping Victorian Cheshire' (British Isles - England -Cheshire: 500, high res.)
• ‘Dorset Coast Digital Archive’ (British Isles - England - Dorset: 890, medium res.)
• ‘Checklist of Hampshire Maps’(British Isles - England - Hampshire: 850, very high res.)
• Guildhall Library's 'Collage' database (British Isles - England - London: about 1,000, low res.)
• ‘E-Map Explorer’ (British Isles - Norfolk: over 600, fairly high res.)
• Landmark /Ordnance Survey (British Isles - Great Britain: about 85,000, high res.)
• Landmark /Ordnance Survey - British History Online (British Isles - Great Britain: thousands, medium res.)
• Rootsweb's 'Old Maps of Great Britain' (British Isles - Great Britain: large selection, some high res.)
• 'Charting the Nation: maps of Scotland and associated archives, 1550-1740' (British Isles - Scotland: 3,558, high res.)
• National Library of Scotland (British Isles - Scotland: over 20,000, high res. [see various individual entries under 'Scotland'])