Location, Location, Old Location: Using Sanborn Maps to Explore the Development of Your Historic Property

Realtors have been known to send off their clients with a small house-warming gift after Closing Day. Although a bottle of bourbon is always nice, another thoughtful gift for new old house owners is a framed copy of a historic map showing the location of their new home.

Old bourbon bottle--a great gift idea!

Old bourbon bottle–a great gift idea!

Historic maps are useful for understanding the development of your property. Fire insurance maps, in particular, are an excellent resource for historical research, planning, and preservation. Old maps are found primarily in the archives and special collections of town halls, and public and university libraries. While a lot of maps have also been put on microfiche, more and more historic maps of all kinds are becoming available in high-resolution, digital format through various libraries. Our very own Cincinnati Public library is in the process of digitizing local maps—including Sanborns—that are available here:  Virtual Library

Sanborn maps were originally created for assessing fire insurance liability in urban areas throughout the United States. These maps include detailed information about town and building information from about 1867 to as recent as 2007. They are characterized by standard symbolization and a very popular aesthetic appeal—so not only is a Sanborn of your street interesting from a historical perspective, it looks neat too! I actually have copies of the 1904 Sanborn hanging on my wall (since the street was split by the page break, I was “forced” to use frame both pages…).

Sanborn map of Garfield Place, 1904

Sanborn map of Garfield Place, 1904

Sanborn maps themselves are large-scale lithographed street plans at a scale of 50 feet to one inch. The maps were packaged in volumes and then updated using overlays until the subsequent volume was produced. Larger cities like Cincinnati, which had a population as high as 325,000 at the turn of the twentieth century, had multiple volumes. The volumes each have a decorative title page and several kinds of indexes with streets and addresses, names, schools, and businesses, and a master index showing the mapped area and the sheet (or page) number for each large-scale map. The maps were highly accurate and include property boundaries, street names and addresses, sidewalks, outlines of each building and outbuilding, the location of windows and doors, fire walls, building use, building construction materials (wood, stone, brick), as well as other elements such as fire hydrants, water and gas mains and even sprinkler systems.

Sanborn 1904 key

Sanborn 1904 key

In the beginning of each volume is a detailed key to the symbols and coding used on the maps. Color was important, so if you are examining digitized black-and-white maps, you are missing out!

To better understand the development of your historic property, looking at through Sanborn maps spanning several decades can be very enlightening. It is possible to learn such things as when additions were added (or subtracted), when outbuildings were constructed (or demolished), if the property boundaries have remained the same, and even when nearby buildings were constructed. I highly recommend a trip to the public library on a rainy day—if we ever have another one of those—or even an internet exploration to see what you can find out about your old home.