On March 3, 1879, an Act of Congress authorized the use of Postage Due stamps. These stamps were unique, since they were the first US stamps that didn’t prepay for the delivery of mail. Instead, they denoted the amount of postage to be collected by the person receiving the mail because it was insufficiently prepaid.
On March 1, 1972, the USPS issued the first stamp in a new series honoring the 100th anniversary of the world’s first national park. Exactly 100 years earlier, Congress established Yellowstone as a national park to protect its unusual features and resources.
On February 28, 1973, the USPS issued the first of seven stamps in its new American Arts Series. The stamps in the series honored artists from several different genres, including painting, music writing, and filmmaking.
On February 16, 1909, stamps printed on an experimental bluish paper were issued. These stamps were part of an effort to prevent paper shrinkage.
On January 7, 1785, mail was carried by an air vehicle for the first time.
On December 1, 1921, the US Post Office Department opened its Philatelic Agency in Washington, DC, to the benefit of stamp collectors.
On June 17, 1844, Boyd’s City Express Post, one of the first local posts in the US, opened in New York City.
On June 14, 2008, the USPS issued the first set of stamps in its Flags of Our Nation Series.
On December 22, 1910, the US Post Office Department issued its first Postal Savings Official Mail stamp.