On February 20, 1792, President George Washington signed the Post Office Act of 1792 creating the U.S. Post Office Department. Pursuant to Article I, Section 8 of the U.S. Constitution, Congress was empowered under the Postal Clause "To establish post offices and post roads."

The United States Post Office (U.S.P.O.) was originally created in 1775 in Philadelphia by an act of the Second Continental Congress under the direction of Benjamin Franklin. The original U.S.P.O. acted as the rival system to England’s postal service in the colonies and was relied upon heavily by the colonists during the American Revolution. However, the original U.S.P.O. did not have a formal system of service. Instead, it relied mainly on private couriers or taverns and shops where couriers could pick up and drop off mail.

On February 20, 1792, President Washington created the U.S. Post Office Department in order to create a more formalized postal service in America. The new U.S. Post Office Department became part of the President’s cabinet and the position of Postmaster General headed the Department. Further, the Post Office Act of 1792 established three other important rules, including: (i) it gave Congress the responsibility to create official postal routes and offices; (ii) newspapers were allowed to be delivered in the mail at low rates for the first time; and (iii) it made it illegal for post office workers to open private mail (which often occurred prior to the Act!).

In 1792, the U.S. Post Office Department charged around six to twelve cents for letters delivered in the mail. At that time, America’s population was around 4 million people and the Post Office contained approximately 75 post offices and 2,400 miles of postal routes.

In 1970, President Richard Nixon signed the Postal Reorganization Act changing the name of the U.S. Post Office Department to its present name as the U.S. Postal Service, which now acts as an independent agency within the federal Executive branch.

Today, the U.S. Postal Service employs around 656,000 workers and maintains around 260,000 vehicles. It is the second-largest civilian employer in the United States, after Wal-Mart, and holds the largest fleet of civilian vehicles in the world! The U.S. Post Office now contains around 37,000 post offices – much more than the 75 it contained in 1792.