City directories began to be published in the United States in the mid-1800's and were very common by the end of the nineteenth century. They were similar to today's telephone directories, but included more information. By themselves, they can establish a person's residence in a particular year. But they also contain clues leading to other genealogical records.
Directories are usually alphabetical by surname and then by given name. It is common to see different spellings of the same person's name over several years, so always search every spelling, and even misplaced letters (like Tahtcher instead of Thatcher). Sometimes a suburb is included in a directory for the larger city, but is separate (it may follow the main alphabetical listing).
Near the beginning of the directory is a list of abbreviations used. It is important to make sure you interpret the directory correctly so you don't make any wrong assumptions. Some directories differentiate between people residing at the home that are related (r) and people who are just boarding (b). They also have abbreviations for different occupations that may not be immediately obvious.
A directory often lists heads of household as well as adult children who reside at the same address, but are working or attending school. This can help establish family groupings. Some directories list the head of household, followed by his wife's name. Persons may be listed under their formal given name, or a nickname, or both in different directory years. When a woman becomes a widow, she will probably be listed alone, but it may include her deceased husband's name. It is a good idea to look for every family surname, including married women, because you will often find older parents living with their adult children, particularly if they are single. Comparing the addresses given for different family members can show whether they were living together, living nearby, or living across town.
One important piece of information in city directories is a person's occupation. Although this information is also included in the census, a directory may also tell what company they worked for, or what position they held. Then you can look up the company in the business directory to find the address, owner, etc. Some employers, such as large corporations, public works, railroads, etc., may have records of their employers that are still extant. Sometimes local historical societies have old business records, so it's a good idea to have as much information as possible about a person's employment history.
Federal censuses were taken every ten years, but many families moved between census enumerations. Finding when they disappeared from one city directory or appeared in another one can give an approximate moving date. Sometimes a directory may even include a family who recently moved and where they moved! City directories usually note whether a person owned or rented their house. If they owned property, they should be listed in land records. You may find deeds showing exactly when they purchased or sold their property.
If a person isn't listed in the directory for a year, check the next several years•they may have just been missed. Or they may have married, or died. A young, single, adult woman will often be listed by herself until she is married, so look for a marriage record around the time she is no longer listed under her own name. And of course, when a person is no longer listed it may be because he or she died, which would lead to death and probate records.
In cities where the 1910 federal census is not indexed, the city directory can help you locate your ancestors. By finding their address in the directory and consulting an enumeration map, you can find the correct enumeration district to search in the actual census.
Some directories have "reverse" street directories, which is arranged by street and then lists the addresses and the persons living there. Sometimes neighbors can be the closest associates of a family, and it is a good idea to note their names in case you get stuck later. It is also a good idea to copy the entire list of people with your ancestor's surname, since it may take a while to piece families together, and you may come across another name later that you want to check.
One last idea for using a city directory is to trace persons whose names appear on other records with your ancestor. For example, you can look up the name of the person who performed a marriage. The directory may state that he was a reverend at a particular church, and then you can search for church records. Tracing the witnesses to a deed or marriage may indicate that they were neighbors or coworkers of your ancestor's family.
City directories can often be found in the local library in print form, but sometimes they may be missing years. Most cities have at least some directories that have been microfilmed, and may be available through your local Family History Center, at the State Archives, or at a university library. You may be able to obtain copies through interlibrary loan, or write to the repository and request copies of the pages containing your surname (be sure to ask for a copy of the list of abbreviations, too!)
For more information about researching in city directories, you may wish to consult the following sources:
Gordon Lewis Remington, "Research in Directories." The Source: A Guidebook of American Genealogy, ed. By Loretto Dennis Szucs and Sandra Hargreaves Luebking. (Salt Lake City: Ancestry, 1997), pp. 385-412. This article contains a complete listing of city directories and which years they were taken.
City Directories of the United States Pre 1860 Through 1901: Guide to the Microfilm Collection. Woodbridge, Connecticut: Research Publications, 1983.