The history of the telephone exchange names in Washington, D. C., as in most significant United States cities, can be divided into three periods:
The current tables derive from only one directory, near the end of the late dial period, when all-number calling was being phased in, and therefore does not include any data from the first two periods or the earliest part of the late dial period. This deficiency will be remedied as data are accumulated so that they can be posted here.
Other regional tables:
|The Baltimore-Washington region|
|Baltimore, Md. (city)||Baltimore, Md. (suburban)||Washington, D. C. (city)||Washington (Maryland suburban)||Washington (Virginia suburban)|
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Last modified February 19, 2015.