Letters were wrapped in oil silk to protect them from moisture, either from stormy weather, fording streams, or perspiring animals.  While a mail of twenty pounds might be carried, the average weight did not exceed fifteen pounds.  The postal charges were at first, five dollars for each half-ounce letter, but this rate was afterward reduced by the Post Office Department to one dollar for each half ounce.  At this figure it remained as long as the line was in business.  In addition to this rate, a regulation government envelope costing ten cents, had to be purchased.  Patrons generally made use of a specially light tissue paper for their correspondence.  The large newspapers of New York, Boston, Chicago, St. Louis, and San Francisco were among the best customers of the service.  Some of the Eastern dailies even kept special correspondents at St. Joseph to receive and telegraph to the home office news from the West as soon as it arrived.  On account of the enormous postage rates these newspapers would print special editions of Civil War news on the thinnest of paper to avoid all possible mailing bulk.

Mr. Frank A. Root of Topeka, Kansas, who was Assistant Postmaster and Chief Clerk in the post office at Atchison during the last two months of the line’s existence, in 1861, says that during that period the Express, which was running semi-weekly, brought about three hundred and fifty letters each trip from California[10].  Many of these communications were from government and state officials in California and Oregon, and addressed to the Federal authorities at Washington, particularly to Senators and Representatives from these states and to authorities of the War Department.  A few were addressed to Abraham Lincoln, President of the United States.  A large number of these letters were from business and professional men in Portland, San Francisco, Oakland, and Sacramento, and mailed to firms in the large cities of the East and Middle West.  Not to mention the rendering of invaluable help to the Government in retaining California at the beginning of the War, the Pony Express was of the greatest importance to the commercial interests of the West.

The line was frequently used by the British Government in forwarding its Asiatic correspondence to London.  In 1860, a report of the activities of the English fleet off the coast of China was sent through from San Francisco eastward over this route.  For the transmission of these dispatches that Government paid one hundred and thirty-five dollars Pony Express charges.

Nor did the commercial houses of the Pacific Coast cities appear to mind a little expense in forwarding their business letters.  Mr. Root says there would often be twenty-five one dollar “Pony” stamps and the same number of Government stamps — a total in postage of twenty-seven dollars and fifty cents — on a single envelope.  Not much frivolity passed through these mails.

Pony Express riders received an average salary of from one hundred dollars to one hundred and twenty-five dollars a month.  A few whose rides were particularly dangerous or who had braved unusual dangers received one hundred and fifty dollars.  Station men and their assistants were paid from fifty to one hundred dollars monthly.