The stamps of the 1920s were dominated by the Series of 1922, the first new design of definitive stamps to appear in a generation. The lower values mostly depicted various presidents, with the 5c particularly intended as a memorial of the recently deceased Theodore Roosevelt, while the higher values included an "American Indian" (Hollow Horn Bear), the Statue of Liberty, Golden Gate (without the bridge, which had yet to be built), Niagara Falls, a bison, the Lincoln Memorial and so forth. Higher values of the series (from 17¢ through $5) were differentiated from the cheaper stamps by being designed in horizontal (landscape) rather than vertical format, an idea carried over from the "big Bens" of the Washington-Franklin series.[citation needed]
Stamp printing was switching from a flat plate press to a rotary press while these stamps were in use, and most come in two perforations as a result; 11 for flat plate, and 11x10.5 for rotary. In 1929, theft problems in the Midwest led to the Kansas-Nebraska overprints on the regular stamps. (See also: Fourth Bureau issue).
From 1924 on, commemorative stamps appeared every year. The 1920s saw a number of 150th anniversaries connected with the American Revolutionary War, and a number of stamps were issued in connection with those. These included the first U.S. souvenir sheet, for the Battle of White Plains sesquicentennial, and the first overprint, reading "MOLLY / PITCHER", the heroine of the Battle of Monmouth.