About digital historical maps
Historical maps from the collections of archives in universities, historical societies, and libraries are increasingly available online as digital collections. Maps are a valuable resource for historical research, showing early land boundaries, the development of roads and railroad lines, and the expansion of cities and towns. The maps are rich resources for any educational setting, providing information for the classroom and personal research.
Most of the online historical maps available from this class guide are, with some exceptions, from academic archives and libraries and historical societies. Some are from a university's map library. One notable exception is the David Rumsey Map Collection, a private collection of 22,000 rare maps, most of which are of North and South America.
Almost all of the collections in this listing are of the local areas of the academic institution that mounted them online, certainly the result of the constant use of the maps by the local researchers. In addition you will also find that there are many maps online of regions, countries, and continents. Many of the collections are in databases where advanced searches are possible, to help you narrow down your search to specific localities, or types.
The possibilities are endless with maps! Enjoy your explorations!
What is a Sanborn map?
Many of the maps you will see linked from the guide are of Sanborn maps. You might be wondering "what are Sanborn maps and why are they so important that numerous archives and libraries are taking the time and expense to digitize them?".
Sanborn map were created by the Sanborn Map Company to assess for fire insurance in cities and towns. The maps show city streets and properties in meticulous detail. Some of the information they include in the maps are types of structure (ex. church, school, business name), railroads and trolleys, street and sidewalk widths, fire walls, and natural features. As a fire insurance map it also includes information indicating the strength of the local fire department, locations of sprinkler systems and fire hydrants, and location of water and gas mains. The maps were constantly updated so in looking at them through the years a researcher can see the changes and growth of a city over time.
So you can see how valuable they are to researchers of any kind, including students doing projects involving the examination of urban environments. It's great that so many of these maps are online!
Philip Hoehn of the University of California - Berkeley Library maintains a Union list (without links) of Sanborn maps at http://www.lib.berkeley.edu/EART/sanbul.html.