Sanborn Fire Insurance Maps at Yale University

Yale University Digital Collections contains 415 selections from the Sanborn Map Company, Fire Insurance maps. There are other collections of these maps available in other university collections also. These series of maps that began publication in 1867 contain an enormous amount of information  about approximately 12,000 towns in the United States. Wikipedia describes the collection as follows:

The Sanborn maps themselves are large-scale lithographed street plans at a scale of 50 feet to one inch (1:600) on 21 by 25 inches (53 by 64 cm) sheets of paper. The maps were published in volumes, bound and then updated until the subsequent volume was produced. Larger cities would have multiple volumes. In between published volumes, updates (new drawings of new or altered buildings or lots) were created and sent out to be pasted on top of the old maps (referred to as ‘slips’) to reduce expense and still preserve accuracy. 

The map volumes contain an enormous amount of information. They are organized as follows: a decorative title page; an index of streets and addresses; a ‘specials’ index with the names of churches, schools, businesses etc.; and a master index indicating the entirety of the mapped area and the sheet numbers for each large-scale map (usually depicting four to six blocks); and general information such as population, economy and prevailing wind direction. The maps include outlines of each building and outbuilding; the location of windows and doors; street names; street and sidewalk widths; property boundaries; fire walls; natural features (rivers, canals, etc.); railroad corridors; building use (sometimes even particular room uses); house and block number; as well as the composition of building materials including the framing, flooring, and roofing materials; the strength of the local fire department; indications of sprinkler systems; locations of fire hydrants; location of water and gas mains; and even the names of most public buildings, churches and businesses.

1911 Sanborn map showing Lagoon Amusement Park in Farmington, Utah

These maps are useful for locating historic buildings and even solving some genealogical mysteries pertaining to property and the location of houses within the communities. Some of the other Sanborn maps collections are located as follows:

• Library of Congress, Sanborn Maps
• Perry-Castañeda Library Map Collection, Sanborn Fire Insurance Maps - Texas (1877-1922)
• PennState University Libraries, Sanborn Fire Insurance Maps 
• Consortium of Academic and Research Libraries in Illinois (CARLI), Sanborn Maps of Illinois

Here is a website with links to many more of the online collections of Sanborn Maps from Michigan State University:

Using Sanborn Fire Insurance Maps Online (Michigan): Links to Sanborn Sites