Mail delivery has seen a multitude of forms over the course of history in the United States. The United States Postal Service was established in 1775 with Benjamin Franklin (is there anything this man didn’t do?) as the Postmaster General.
By the early 1830s, mail was being delivered by locomotives. Of course, there was the Pony Express with its short run of mail delivery by horseback through what was still a vast wilderness in the west. Otherwise, foot soldiers and horse drawn carriages made the routes to get people their mail until 1899. That’s when automobiles first were utilized for delivery.