Follow these Associated Press guidelines for the U.S. states:
STANDING ALONE: Spell out the names of the 50 states when they stand alone in textual material.
DON'T ABBREVIATE EIGHT: The names of eight states are never abbreviated in text: Alaska, Hawaii, Idaho, Iowa, Maine, Ohio, Texas and Utah.
ABBREVIATIONS REQUIRED: Use the state abbreviations listed at the end of this section in conjunction with the name of a city, county, town or village in text. Place one comma between the city and the state name, and another comma after the state name.
Examples: He travelled from Nashville, Tenn., to Austin, Texas. Cook County, Ill., is where Jane's family lives.
STATE ABBREVIATIONS: Following are the state abbreviations. ZIP code abbreviations are in parentheses. Use the two-letter Postal Service abbreviations only with full addresses, including ZIP code.
These are the ZIP code abbreviations for the eight states that are not abbreviated in text: AK (Alaska), HI (Hawaii), ID (Idaho), IA (Iowa), OH (Ohio), TX (Texas) and UT (Utah).
WASHINGTON, D.C.: Use state of Washington or Washington state when necessary to distinguish the state from the District of Columbia (Washington, D.C.).