The United States Postal Service (USPS) is a government-run corporation which oversees the mail system of the United States of America. The American postal system was founded by Benjamin Franklin in 1775.
Unlike its commercial competitors such as UPS, the USPS is the only mail carrier which delivers mail to the North Pole. This distinction played an important role in the special A Muppets Christmas: Letters to Santa, in which the Muppets had to deliver letters to Santa Claus by hand after the local post office had closed. The song "Delivering Christmas," which honors the postal workers who deliver the letters to Santa, was later made available on an album sold by the Postal Service.
Each Christmas season, the Postal Service uses a special holiday cancellation, usually featuring a licensed character. Kermit the Frog appeared on the 2009 holiday cancellation for holiday cards and letters mailed in the month of December.
The USPS has also honored the Muppets with postage stamps: Big Bird's likeness graced a 1999 stamp honoring events of the 1970s, while Jim Henson and the cast of The Muppet Show appeared on a set of stamps issued in 2005 to honor Kermit's 50th anniversary. Henson and Rowlf also promoted the 1986 Love Stamp.
- The Postal Service is shown multiple times in The Sesame Street Dictionary. Big Bird is shown to mail a letter, a mail woman delivers a letter to Bert and Ernie, Marshal Grover goes to the post office to mail a letter to his Mommy, and Farley goes to buy a stamp.
- Herry Monster runs over a mailman who delivers him an invitation to a tea party in the book My Doll Is Lost!.
- Uncle Traveling Matt sent his postcards via USPS, and his first encounter with a mailbox is shown in the book The Tale of Traveling Matt.
- A U.S. Mail Woman interrupts Grover's narration when she delivers a letter to Little Red Riding Hood in Grover's Little Red Riding Hood.