I have been working in 1902 Portugal for some time now, and one thing I’ve had trouble with has been street names. Particularly when a country has been through a revolution or two since the date I’m working with. Old regime street names fall out of favor, and newly important guys get the streets renamed after them.
While my biggest issue in Porto was street names changing due to the revolution, my biggest problem in Saratoga Springs was buildings burning down. Either way, it’s important to think about change when you’re using your old setting.
When I’m looking at a modern-day map of Porto, I can’t count on any of the street names being the same as they were in 1902. In addition, some parts of the city we demolished and rebuilt post 1911, when the new regime took over, putting in the new municipal building and the wide avenues on either side of it. The buildings on that street -look- old, as if they came from the 1700s, but in truth they’re all post 1911. That means they can’t appear in my novel, can they?
So what’s a writer to do?
Well, if you’re writing in a post 1827 world, the Baedeker (or other travel guides) can possibly be your salvation. A lot of people have been selling off maps from travel guides and atlases, via such venues as Ebay or Etsy. I’ve picked up some nice period maps for Portugal that have been very helpful. I’ve also found a couple of old travel guides for Saratoga Springs that have turned up all sorts of interesting tidbits (including a menu from the U.S.Hotel!).
But these do cost money–this is the kind of thing you won’t find in a library. OTOH, usually the seller posts a photograph of the map when they’re trying to sell it, and you could copy that photo to a file and use that (although that’s never as good as having the real thing)*.
So keep in mind that there are resources out there, even if not in the most obvious place. Put your city and the year (try a couple of adjacent years, too) into Google, and see what crops up!
And if all else fails, fudge it. Remember…if you can’t find that information after a reasonable amount of time searching the internet, then most of your readers can’t either.
*It’s better to buy if you an afford it at all, as otherwise it’s approaching piracy.