The United States Postal Service dates back to the late 1690s, when individual Colonies regulated the management of Personal and Public Mail. With the establishment of The Continental Congress during The American Revolution, it too was determined that a centralized Mail System be created and regulated. Originally an independent Institution, The US Postal Service became Federalized in 1792. In an Age before Trains and Aircraft, Mail took many weeks if not months to reach certain locations within The United States and it’s Territories. The most common method of delivery was by Horseback and Ship. The Mail Service hence contracted with Private Shipping concerns to deliver bulk Mail from Port to Port.
Although several Companies were dedicated exclusively to such work, any such Vessel so contracted was authorized to fly a Government Mail Pennant. Such Flags were flown on the far end Mast at the Stern. The general design of such Pennant style Flags were roughly 8 to 12-feet in length. Based on a “Swallow-Tail” pattern, these Flags were predominantly Red, bordered in Blue. In the Upper Left Canton, a Blue Federal Eagle was placed (near The Hoist). In the Center of the Field was the wording “United States Mail”. During World War I into the 1930s, US Military Vessels carried Mail as well – to Military Personnel Worldwide. In these cases, such Ships flew a smaller squared Flag. Blue in entirety, they bore the White lettering “USM”. Display was under all other Military Flag Devices.
The US Mail no longer uses Sea Fleets to transport Mail as a rule. The Department itself is recognized by the display of a Flag. The official Colors of The Postal Service is a 6 X 4 foot Flag. The Field is Blue with a centered image of a “Running Pony” with Rider, delivering The Mail. Thus symbol is in reference to the days when the independent “Pony Express” delivered The Mail (1850s). (4) Stars border the symbol, each representing the original Colonies who developed a Postal Service, before the founding of a National Service.