A design drawing for the U.S. Mail's Pac Fax mailbox, as seen in Courthouse Square. Note that the box here advertises a "30 Second Service" as opposed to the ".05 Second Service" seen on-screen.
The U.S. Mail — or the United States Postal Service — was the official system in the United States of America of carrying and delivering letters and parcels.
In 2015, the U.S. Mail also ran a fax service called Pac Fax, where public mailboxes had fax machines built in so that people could send faxes while on the move. One such mailbox was present in Courthouse Square, Hill Valley and advertised a “.05 Second Service”.
According to Emmett Brown, the US Weather Service was more efficient than the Post Office. Hopefully, Doc was only joking.
