Rural Free Delivery (RFD), since 1906 officially rural delivery, is a program of the United States Post Office Department to deliver mail directly to rural destinations. The program began in the late 19th century. Before that, people living in rural areas had to pick up mail themselves at sometimes distant post offices or pay private carriers for delivery.
Rural Free Delivery vehicle (from Popular Mechanics, September 1905)
Rural carrier in an early electric vehicle, circa 1910
United States Post Office Department
The United States Post Office Department was the predecessor of the United States Postal Service, established in 1792. From 1872 to 1971, it was officially in the form of a Cabinet department. It was headed by the postmaster general.
First U.S. postage stamps, authorized by Congress March 3, 1847. Earliest known use of the 5¢ Franklin is July 7, 1847, and the 10¢ Washington is July 2, 1847.
Mineral Wells, Texas, post office, built between 1911 and 1913
Mail truck loaded with gold leaving the New York City Assay Office in 1941