Whether you're looking for a historic map to overlay in Google Earth, or hoping to find your ancestor's town of origin, these online historical map collections offer don't miss resources for any genealogist. Find topographic, panoramic, survey and other historical maps, many available for free online viewing and downloading.

1. David Rumsey Historical Map Collection

Browse through over 30,000 high-resolution digital maps and images from the David Rumsey Historical Map Collection, one of the largest private collections of historic maps in the U.S. This free online historical map collection focuses primarily on cartography of the Americas from the 18th and 19th centuries, but also has maps of the world, Asia, Africa, Europe, and Oceania. They keep the maps fun too! Their LUNA map browser works on the iPad and iPhone, plus they have selected historical maps available as layers in Google Maps and Google Earth, plus a neat virtual world collection on Rumsey Map Islands in Second Life.More »

2. American Memory - Map Collections

This outstanding free collection from the U.S. Library of Congress contains more than 10,000 online digitized maps from 1500 to the present, depicting areas all over the world. Interesting highlights of the historical map collection include birds-eye, panoramic views of cities and towns, as well as military campaign maps from the American Revolution and Civil War. The map collections are searchable by keyword, subject and location. Since maps are often assigned to only one particular collection, you'll achieve the most complete results by searching at the top level.More »

3. Perry-Castañeda Library Map Collection

Over 11,000 digitized historical maps from countries around the world are available for online viewing in the historical section of the Perry-Castandeda Map Collection of the University of Texas at Austin. The Americas, Australia and the Pacific, Asia, Europe and The Middle East are all represented on this extensive site, including individual collections such as pre-1945 Topographic Maps of the United States. Most maps are in the public domain, with those under copyright clearly marked as such.More »

4. Old Maps Online

This mapping site is really neat, serving as an easy-to-use searchable gateway to historical maps hosted online by repositories around the world. Search by place-name or by clicking in the map window to bring up a list of available historical maps for that area, and then narrow further by date if needed. The search results take you directly to the map image on the website of the host institution. Participating institutions include the David Rumsey Map Collection, the British Library, the Moravian Library, and the National Library of Scotland.More »

5. Historic Map Works

This subscription-based historical digital map database of North America and the world includes over 1.5 million individual map images, including a large collection of American property atlases, along with antiquarian maps, nautical charts, birds-eye views, and other historical images. Each historical map is geocoded to allow address search on a modern map, as well as overlay into Google Earth. This site offers individual subscriptions; alternatively you may be able to use the site for free through a subscribing library.More »

6. old-maps.co.uk

Part of a joint venture with Ordnance Survey, this digital Historical Map Archive for mainland Britain contains historical mapping from Ordnance Survey's Pre and Post WWII County Series mapping at various scales dating from c.1843 to c.1996, as well as Ordnance Survey Town Plans, and interesting Russian Maps of UK locations mapped by the KGB during the Cold War era. To locate maps, just search by address, place or coordinates based on modern geography, and the available historical maps will be displayed. All map scales are free to view online, and can be purchased as electronic images or prints.More »

7. Maps of Australia

The National Library of Australia has a large collection of historical maps. Learn more here, or search the NLA Catalogue for records to over 100,000 maps of Australia held in Australia's libraries, from the earliest mapping to the present. Over 4,000 map images have been digitized and can be viewed and downloaded online.More »

8. A Vision of Britain Through Time

Featuring primarily British maps, A Vision of Britain Through Time includes a great collection of topographic, boundary, and land use maps, to complement statistical trends and historical descriptions drawn from census records, historical gazetteers, and other records to present a vision of Britain between 1801 and 2001. Don't miss the link to the separate website, Land of Britain, with a much higher level of detail limited to a small area around Brighton.More »

9. University of Virginia: Geospatial and Statistical Data

Provided by the University of Virginia, the Geospatial and Statistical Data Center provides an easy to use Historical Census Browser with nation-wide census data, and a Virginia Gazetteer Database with geographic data and maps documenting over 51,000 Virginia features and places.More »

10. Atlas of Historical U.S. County Boundaries

Explore both maps and text covering the creation, historical boundaries, and all subsequent changes in the size, shape, and location of every county in the fifty United States and the District of Columbia. The database also includes non-county areas, unsuccessful authorizations for new counties, changes in county names and organization, and the temporary attachments of non-county areas and unorganized counties to fully functioning counties. To lend to the site's historical authority, the data is drawn primarily from the session laws that created and changed the counties.More »