The William & Mary Libraries have some maps databases, most notably the Digital Sanborn Maps, but in most cases your best bet are digital collections online or bound collections of maps (atlases) organized around specific topics.
Search maps as a SUBECT and in the second box put the location as a subject or keyword.
Limit publication date after the search results load, using the tools on the left side of the screen, next to the results.
This will also include materials in Special Collections, as well as materials in the general collection or digital collections.
This approach also works in WorldCat. Search maps as a SUBJECT and the location as a subject.
If you see a map of interest, look online to see if it has been scanned.
If it is held only by a few libraries or archives, go to their website to see if it has been scanned.
Maps in archival collections are very unlikely to be ILL'd, and scanning will likely include a charge.
Use the Maps tab to sift through results more swiftly.
Finding subject-related or themed maps
Search maps as a subject, and your topic as a subject or keyword.
Do NOT limit to publication date until you look at the results; if you're interested in the 19th century, there may be a 21st century publication with compiled/reprinted maps. For example, a subject search for maps AND "African Americans" brings up recent publications containing collections of historic maps.
This exact same approach also works in WorldCat. Search Maps and your topic as subjects in the advanced search sections of WorldCat
"atlas" is NOT a subject within the Library of Congress system. The best way to find them are to use maps as a subject and limit to books & ebooks.
Add your topic or location in the second search box. Do not limit to a specific time period yet, as this will remove historical atlases that were published later. You can, however, narrow publication date after the initial search.
NOTE if you find an atlas in worldcat, we can probably ILL it, but look in googlebook, hathitrust, and internet archive to see if a digital copy exists. This will speed up the access process.
Knowing the type of map you want helps narrow where to look. This is a general list of types of maps you may encounter.