Over the course of U.S. history, county boundaries and names changed, and large counties were broken up into smaller ones. In 1883, for example, Hernando County was broken up into 3 separate entities, and Citrus and Pasco counties were born. An ancestor who shows up in the 1880 census as a resident of Hernando County may have been living in what is now Citrus or Pasco.
The Atlas of Historical County Boundaries created by the Newberry Library in Chicago, will tell you what county your ancestors lived in. Make sure you look at the "Using the Atlas" section to get the most from the database.
Back in the late 19th and early 20th centuries, when the mail moved slowly and some citizens had to travel a good distance to check for mail, letters often accumulated at the post office. The Postmaster would place lists of names from unclaimed letters in the local newspaper.
These lists may be helpful for genealogical research. You can use your library card to access newspapers.com on the library's website and search "unclaimed letters" or "list of letters", along with a date range and location.
You will find newspapers.com under Research Tools on the home page.
From Ted.com in 2018.