ChicagoAncestors.org is a searchable interactive mapping site. Type in an address, and you’ll get a map showing the location, along with nearby churches, sites of crimes and more. Roll over the map markers for each place to see data such as addresses, date and type of crime, associated library resources or links to online images. (The data come from sites such as Homicide in Chicago and Jazz Age Chicago.)
There’s also a keyword search box, Type in St. Thomas, and you’ll see locations of churches with that name.
You’ll want to read the search tips. You need to use address conversion tools for addresses before 1909, and leave off street descriptors such as Ave. or Rd. For example, I entered 137 DeKoven St., which is where Mrs. O’Leary (whose cow did not start the Chicago Fire) lived in 1871, and got nothing. But after downloading the 1909 street number conversion book (under Tools) as a large PDF, I looked up the address, searched on 558 Dekoven, and got my map.
Wondering if Mrs. O’Leary might’ve attended nearby St. Wenceslaus church, I clicked on its name and got its years in organization and a list of its available records at the Family History Library.
Registered ChicagoAncestors.org users can click to add their own comments to map points or map their own genealogical information and save it to their profile.
Click Tools to get street guides, more maps and other useful links; and click What’s New for updates from the Webmasters.
Here, Mrs. O’Leary’s address is the blue star, and the yellow dot is the site of nearby criminal activity.