A good U.S. road atlas will suffice to help you locate most cities, even tiny ones. But many 19th century hamlets have vanished, in which case you'll have a harder search. Your local library has resources , or you can try the Internet. While we're at it, I hope you noticed in my example above that I spelled out Washington. Please do that.
Geographical abbreviations change with time.
With any luck, your genealogical records are going to survive for a few centuries. Heaven only knows how they'll abbreviate Washington in 2199. It's also nice to be kind to foreign genealogists. If you put your genealogical records in a repository on the Web or in the archives of the Church of Jesus Christ of Latter-day Saints, they will be accessed by people who live in other countries and speak other languages. OK, I figure that one is safe.