Postage stamps and bried postal history of Canal Zone
In 1904, the postal authority of Panama Canal Zone used the stamps of Panama and the United States with various overprints of ‘CANAL ZONE’.
Extensive research by many philatelists have identified many varieties, many common but some quite rare. The overprints were stopped in 1939.
In 1928, the Canal Zone issued a definitive series with the inscription of "CANAL ZONE POSTAGE". These stamps adopted designs relating to the construction of the canal.
In 1939, a new series of sixteen stamps was released in commemorating the 25th anniversary of the canal’s completion. These stamps showed the "before" and "after" views of various points along the canal. The inscription on the stamps was changed to just "CANAL ZONE" in the 1960s.
The most famous Canal Zone stamp was the four cent stamp error stamp (Scott #157a) issued in October 1962, for the opening of the Thatcher Ferry Bridge, the first elevated bridge connecting the two sides of the Canal. Apparently, one pane of fifty stamps was released without the silver ink used to depict the Bridge.
In late October 1978, Panama took over the administration of the postal services and soon, Canal Zone stamps became invalid.