The 3-cent Arriving at Chagres regular issue stamp (Scott 142) is the low value of the four-stamp series commemorating the centennial of the California Gold Rush. Since gold seekers arrived by the thousands on the Atlantic side of the Isthmus, a scene showing a sailing vessel was selected for the stamp. The ship appears below San Lorenzo, the old Spanish fort that overlooked the mouth of the Chagres River. The mouth of the Chagres River was the entryway to the then-department of Panama now known as Colombia. A makeshift town called 'Yankee Chagres' was soon established across the Chagres River from the fort, and from there the Argonauts traveled up-river to the Pacific Ocean port at Panama City. This 3-cent stamp depicts a small boatload of 49ers heading towards the beach, the initial step on their trek across the Isthmus of Panama.
Some 500,000 of the 3-cent Gold Rush Centennial stamps were printed, all of which were sold over time.
This stamp is usually found either on a regular or 'boat-mail' letter addressed to the United States or together with its sisters on first day covers. All of the Canal Zone post offices of the time were equipped to postmark first day covers, and as a result collectors seek out complete sets of stamps from each office. The 3-cent Gold Rush Centennial stamp may also be found on non-philatelic mail in combination with other stamps. Multiples and usages to foreign destinations and special services such as registration are popular.