If you're interested in urban history, fire insurance maps by the Sanborn and Bromley companies are a great resource. They show building use, company names, and even building materials at varying increments through time. You can try either of these library resources:
Fire Insurance Maps Online (Bromley, Sanborn in color)
Digital Sanborn Maps. (Black and white)
Image above: Plate 19R, Bromley 1894 Atlas of Cambridge
FUTURE TRIP? Once we're able to return to campus, you can stop in at the Harvard Map Collection, on the Pusey Corridor of Lamont Library. There you can view the original color atlases from which many of these digitized maps were made.
Maps like these can be useful for any type of US urban historical work later in your studies, and if you're visually oriented, they might reveal new questions to you.