United States Mail Steamship Co.

The United States Mail Steamship Company operated the eastern portion (Chagres to New York) of the Panama route between New York and San Francisco.  The Pacific Mail Steamship Company operated Between San Franciscio and Panama City.  The overland portion was operated by various firms before the completion of the Panama Railroad.  With the completion of the Panama Railroad, the western terminus of the steamship route was relocated from Chagres to Aspinwall (now known as Colon).  The United States Mail Steamship Co. operated the route beginning in December 1848, and continued until 1859.  In 1860, the contract was awarded to Vanderbilt's Atlantic and Pacific Steamship Company.  In 1865, the Pacific Mail Steamship Company took over the contract. 

Panama City, Colombia, December 19, 1857, carried under cover by Wells Fargo Express from Aspinwall to New York by steamship Northern Light departed Aspinwall December 19, arrived New York December 27, manuscript “California” most likely applied by Wells Fargo, perhaps indicating that cover arrived with the California mails, then turned over to Boyd’s City Express Post for local delivery.

Bogota, Colombia, January 28, 1858, "BOGATA FRANCA" marking rated 25 centavos crossed out, 50 centavos marking on back, double rate local charge to Aspinwall, per Empire City to New York, "N. YORK STEAMSHIP" circular marking manuscript rated 20¢, double 10¢ cent steamship rate.

Lima, Peru, December 12, 1858, “PAID-TO-PANAMA” marking in black, by Pacific Steam Navigation Co. packet to Panama City and then United States Mail Steamship Co. to New York.  New York "STEAMSHIP 10" marking, rated 10¢ due incoming steamship letter for distance under 2,500 miles.