The Frances Woodhouse History Room in the Freeport Public Library (100 Douglas Street, Freeport, IL) maintains Freeport City Directories for most years beginning 1877 through 2016. These directories can be viewed only in the History Room. You can make copies of pages at 10¢ per page.
City directories are a wonderful resource for tracing local families. Listed both by house address and alphabetically by surname, individuals perhaps not otherwise found may be located in a directory. Long-time residents can be tracked year by year by where they lived.
Perhaps a shift from rental to homeownership indicates a job change. Many of the early directories even list occupation and the name of the firm where the individual worked. A move might help corroborate when a child was added to the family.
Considering a house history? City directories are the invaluable resource for learning who actually lived in a house, as opposed to who owned the property. These are a wonderful resource to support your deed searches and provide the starting point for family genealogy of a home’s residents.