In 1775, when Benjamin Franklin was appointed the first Postmaster General, the U.S. Post Office was born. So important was the Postmaster General that in 1829 this position was included among those in the President's Cabinet. As America began to grow and new towns and villages began to appear, so too did the Post Office along with them. The dates and postmarks generated from these places often has provided the historian with a window into a given time and place in question. Each postmark is uniquely distinctive with its own name of state and town, in addition to its distinctive date.

Congress finally provided for the issuance of stamps by passing an act on March 3, 1847, and the Postmaster-General immediately let a contract to the New York City engraving firm of Rawdon, Wright, Hatch, and Edson.[22] The first stamp issue of the U.S. was offered for sale on July 1, 1847, in New York City, with Boston receiving stamps the following day and other cities thereafter. They consisted of an engraved 5-cent red brown stamp depicting Benjamin Franklin (the first postmaster of the U.S.), and a 10-cent value in black with George Washington. Like all U.S. stamps until 1857, they were imperforate.

The 1861 stamps had in common the letters "U S" in their design. To make them differentiable from the older stamps at a glance, all were required to have their values expressed in Arabic numerals (in the previous series, Arabic numerals had appeared only on the 30¢ stamp). The original issue included all the denominations offered in the previous series: 1¢, 3¢, 5¢, 10¢, 12¢, 24¢, 30¢ and 90¢ stamps. Numerals apart, several of these are superficially similar to their earlier counterparts—particularly because Franklin, Washington and Jefferson still appear on the same denominations as previously. The war greatly increased the amount of mail in the North; ultimately about 1,750,000,000 copies of the 3¢ stamp were printed, and a great many have survived to the present day, typically selling for 2-3 dollars apiece. Most are rose-colored; pink versions are much rarer and quite expensive, especially the "pigeon blood pink".

During World War II, production of new U. S. 3¢ commemorative stamps all but ceased. Among the three issues that appeared in 1942[40] was the celebrated Win the War stamp,[41] which enjoyed enormously wide use, owing partly to patriotism and partly to the relative unavailability of alternatives. It presents an art deco eagle posed in a "V" shape for victory surrounded by 13 stars.[41] The eagle is grasping arrows, but has no olive branch. A notable commemorative set did, indeed, appear in 1943–44, but its stamps, all valued at 5 cents, were not competitive with the Win the War issue. This was the Overrun Countries series (known to collectors as the Flag set), produced as a tribute to the thirteen nations that had been occupied by the Axis Powers.