6.1.1 Post Code Abbreviations

Names of states, provinces, territories, and other geographic entities should normally be spelled out in running text when they appear on their own. Abbreviations may be used in parentheses, notes, tables, bibliographies, mailing addresses, or other compact references where space and clarity warrant them.

When abbreviations are used, follow one system consistently. This manual prefers the standard two-letter postal forms for U.S. states and Canadian provinces, such as OH, MA, CA, and ON, rather than older forms such as Ohio, Mass., Calif., or Ont. If a publisher requires a different system, authors should follow that requirement throughout the manuscript.