The Society: Holidays: (Presidents' Day Holidays )

Until 1971, the United States observed both February 12 and February 22 federal public holidays. On February 12, the nation honored the birthday of Abraham Lincoln, and on February 22, the nation honored the birthday of George Washington. In 1971 President Richard Nixon issued a proclamation establishing Presidents' Day, a single federal public holiday, which would honor all presidents of the United States of America. Presidents' Day is observed on the 3rd Monday of February. Sites included in this section focus on observances of Presidents' Day. Specific information about George Washington, Abraham Lincoln, or other U.S. presidents is available in linked categories. Presidents' Day Holidays Society.

Colloquially, it is now widely known as Presidents Day, a term deliberately coined to change the holiday into one honoring multiple presidents, and is often an occasion to remember all the presidents, not just George Washington. (wikipedia)