High Quality Content by WIKIPEDIA articles! The Pacific Mail Steamship Company was founded April 18, 1848 as a joint stock company under the laws of the State of New York by a group of New York City merchants, William H. Aspinwall, Edwin Bartlett, Henry Chauncey, Mr. Alsop, G.G. Howland and S.S. Howland. These merchants had acquired the right to transport mail under contract from the United States Government from the Isthmus of Panama to California awarded in 1847 to one Arnold Harris.