Early California Mail

“[U]nder Mexican rule, California had depended for mail service upon the irregular arrival of supply vessels and couriers, and the convenience of the commandants. The United States military authorities improved upon this by the. establishment of a regular service between their posts, which was open to the public; and by sending occasional messengers to Washington City.April 17, 1848,  the military authorities dispatched ‘Kit’ Carson with the first United States mail ever carried overland from the Pacific to the Atlantic.”