Two-Letter Abbreviations of States in The U.S.
In October 1963, two-letter state abbreviations became effective in the U.S, thanks to the United States Postal Service (USPS). Postal services globally recognized the state abbreviations around the world. For instance, MO is the state of Missouri abbreviation; WY is for Wyoming, while Pennsylvania uses PA as its 2-letter abbreviation. Until 1969, the abbreviation for … Read more