* Seal
* Flag

Seal

Mercury, a post rider, and now the eagle have symbolized the postal system in the United States at various times in its history.
In 1782, Postmaster General Ebenezer Hazard used the figure of Mercury, the messenger of the gods and the god of commerce and travel in Roman mythology. Mercury was shown riding on clouds, with winged feet and a staff in his right hand. A serpent-entwined staff was placed in Mercury's extended left hand by Postmaster General Gideon Granger in June 1808, until Postmaster General John McLean modified the seal again in 1824 by placing Mercury's right hand at shoulder height.
The official seal used by the Post Office Department from 1837 to 1970 pictured, as directed by Postmaster General Amos Kendall, "a post horse in speed, with mail bags and rider, encircled by the words 'Post Office Department, United States of America."' It is believed this seal was inspired by Benjamin Franklin. When Franklin was selected Postmaster General by the Continental Congress, he issued a circular letter throughout the colonies, bearing a rude woodcut of a post rider on horseback, with saddle bags behind him for carrying the mail.
On August 12, 1970, the day President Nixon signed into law the Postal Reorganization Act converting the Post Office Department into an independent establishment of the executive branch, the Postal Service announced adoption of a new seal. It featured a bald eagle poised for flight on a white field, above red and blue bars framing the words "U.S. Mail" and surrounded by a square border with the words "United States Postal Service" on three sides and nine five-pointed stars at the base. The stars carry no special symbolism.

Flag

The United States Postal Service flag is a five-color version of the new seal, placed on a white, rounded square background on an Old Glory blue flag base.