The Sanborn Fire Insurance Map Company, established in 1867, compiled and published maps of U.S. cities and towns for the fire insurance industry to assess the risk of insuring a particular property. The maps are large scale plans of a city or town drawn at a scale of 50 feet to an inch, offering detailed information on the use made of commercial and industrial buildings, their size, shape and construction material. Some residential areas are also mapped. The maps show location of water mains, fire alarms and fire hydrants. They are color-coded to identify the structure (adobe, frame, brick, stone, iron) of each building.If one isn't sure about street name changes, or renumbering, the Sanborn maps can help you plot where an address is on a current map by pointing out cross streets and other landmarks that don't change with time, such as parks. You can also find out what else was in the neighborhood, such as businesses, schools, or houses of worship.
The Missouri Sanborn maps online for St. Louis city are mostly from 1909. All four of my paternal second-great grandfathers were in St. Louis in 1909 - Selig Feinstein, Moshe Leyb Cruvant, Morris Blatt, and Samuel Newmark. They all moved around a bit as well, and when I added in some work addresses I had, there were a lot of addresses I could look up.
From the city directories I knew that from 1896 to 1906 the Feinsteins were at 1122 North 8th. My great-grandfather, Herman Feinstein, was age 10-20 during those years.
I think I have a good idea where my great grandfather probably went to school. The map above is from 1909, so there is no guarantee that the school behind where my great grandfather grew up was there for the decade prior.
The cross street at the top of the map is Biddle, and the Cruvant family lived at 701 Biddle briefly during 1897. The Blatts lived in the 1000 block in 1896. So the three families weren't too far apart during those years.