[Acronym] US or U.S. [Expansion] United States [Notes] 
Does not need to be written out in full on first use, nor provided on first use in round brackets after the full name if written out. Some American editors prefer to use "U.S." However, use a consistent style within the same article; use "US" in articles with other national abbreviations, e.g. "UK" or "UAE". USA, U.S.A. and U. S. of A. are generally not used except in quoted material (see WP:Manual of Style#US and U.S.).