The Penny Post is any one of several postal systems in which normal letters could be sent for one penny. Five such schemes existed in the United Kingdom while the United States initiated at least three such simple fixed rate postal arrangements.
In England, the postal service, from 1660 General Post Office, had developed into a monopoly, affirmed by Oliver Cromwell in 1654, for the collection and carriage of letters between post towns, however, there was no delivery system until William Dockwra and his partner Robert Murray established the London Penny Post in 1680. They set up a local post that used a uniform rate of one old penny for delivery of letters and packets weighing up to one pound within the cities of Westminster and London as well as in Southwark. Several deliveries took place a day within the city, and items were also delivered to addresses up to ten miles outside London for an extra charge of one penny. In 1683 Dockwra was forced to surrender the Penny Post to the English Monarchy for circulating what were considered seditious newsletters sharply criticizing the Duke of York, who was in charge of and directly benefited from the General Post Office.
In 1765, Parliament authorized the creation of Penny Posts in any town or city of the kingdoms of Great Britain and Ireland. The single postage rate of one penny was charged within the area, calculated by weight. By the beginning of the 19th century there were many of these, identifiable on covers, with markings such as "PP", "Py Post", or "Penny Post" along with the name of the town.