Maps are one of the best resources you can find to see how locations and properties have changed over time. When it comes to historical maps for moderately-sized cities from the 19th and early 20th century United States, it is hard to beat Sanborn Fire Insurance Maps. The Sanborn Map Company created large-format lithographed maps so that fie insurance companies could make informed risk assessments for municipalities.
The Library of Congress has an extensive collection (32,461 on 2020-07-21) available online. The University of Florida has a list of State institutions that received copies of the Sanborn Maps. Many of these entities have indexed and made copies available online, as well.
When you first look at a Sanborn Map, you'll notice a lot of abbreviations and patterns. All of these cryptic symbols mean something and can help unlock hidden information about the buildings you're researching. It's helpful to keep some cheat sheets at-hand to guide you through your mapping journeys.
This book from The University of Michigan could be indispensable.
If you want a quick cheat sheet of the abbreviations, **this two-page printable from Environmental Data Resources** might be just the thing.