The Cross-Street Index A feature found in most twentieth-century city directories is a cross-street index.
The main listing of names in the book is an alphabetical listing by the names of the residents.
Before the Internet, the Polk directories were the primary People-Finder service in America.
Today, however, the older city directories are almost exclusively limited to public libraries, college libraries, and archives nearest to the city in question.
For example, New York City’s directories go back to the 1730s, and they are very complete through 1933, the last year a full every-name city directory was produced for Manhattan.
The New York Public Library has an outstanding collection of the old city directories for all five boroughs of New York City.
The previous article, “Online Resources for Finding Living Relatives (Part 1 and Part 2),” identified many of the websites where white pages, yellow pages, and current city directories are found.