List of U.S. state and territory abbreviations

However, they accepted these abbreviations only because of their popularity, preferring that patrons spell names out in full to avoid confusion.

Originally Nebraska was "NB"; but, in November 1969, the Post Office changed it to "NE" to avoid confusion with New Brunswick in Canada.

The United States Postal Service (USPS) has established a set of uppercase abbreviations to help process mail with optical character recognition and other automated equipment.

[16] However, the Chicago Manual of Style now recommends use of the uppercase two-letter abbreviations, with the traditional forms as an option.

[4] Canada likewise chose MB for Manitoba to prevent conflict with either Massachusetts (MA), Michigan (MI), Minnesota (MN), Missouri (MO), or Montana (MT).

The twelve cases where USPS and USCG abbreviations differ are listed below and marked in bold red in the table above; they include three inland states with a small Coast Guard contingent.