Includes more than 660,000 Sanborn maps charting the growth and development of more than 12,000 American towns and cities. Digital Sanborn Maps was created from ProQuest Information and Learning's microfilm collection of 660,000 Sanborn Maps, which were filmed from the Library of Congress' collection. The Library's Sanborn collection includes all maps submitted to the Library through copyright deposit and a set of maps transferred to the Library from the Bureau of the Census. Maps from the Bureau of the Census include corrections issued by the Sanborn Company that were pasted over the original map sheet. Maps acquired through copyright deposit remain in their original form. The coverages are listed, state by state, in Fire Insurance Maps in the Library of Congress. Washington, 1981. (Maps Z 6026 I7 U58 1981). Includes textual information on construction details (for example, steel beams or reinforced walls), building use (ranging from symbols for generic terms such as stable, garage, and warehouse to names of owners of factories and details on what was manufactured in them ; in the case of large factories or commercial buildings, even individual rooms and the uses to which they were put are recorded on the maps), and other building features (such as pipelines, railroads, wells, dumps, and heavy machinery).