The United States Postal Service maintains a database comprised of 35M records
validate address information provided by new account applicants. The database will validate the
existence of every street, town, city, state and zip code in the United States, and will allow
for the system to verify if a street address is a valid address within a range of addresses. For
instance, if someone states that they live at 1742 V Street, NW, Washington, D.C. 20009-2996, the
system will confirm that 1742 is an address that could fall within the list of addresses for that
street, that V street is a street in Washington, D.C., that Washington is a city in the District
of Columbia, that 20009 is a zip code in Washington, and that 2996 is the proper zip+4 suffix code
for the 1700 block of V Street. The database contains information on all 50 states, Puerto Rico,
the Virgin Islands, and the Federated States of Micronesia, Guam, the Mariana Islands, the Marshall
Islands, Palau, Samoa, and American Overseas Military Addresses.
Individual address is checked to ensure that it is a valid US address.