The Library of Congress Geography and Map Reading Room has a collection of Sanborn fire insurance maps for the entire country including parts of Schuylkill County. Some of these maps are available online, but it looks like most are only in print and must be used by researchers at the Library of Congress. Still, you can check the site to find out what years are available for which communities. Follow this link to view the list of Pennsylvania cities. It may be worth taking a trip to Washington, DC to use them!
Keep in mind that smaller communities were sometimes included in maps for larger communities; for instance, in 1891 a fire insurance map of Pottsville also included the communities of Minersville, Port Carbon, St. Clair, Orwigsburg, and Cressona.
You can get complete contact information on the contact page, including their Ask-A-Librarian feature.
If you know of any other reliable sources for Sanborn fire insurance maps, please let us know and we will spread the word!