America: our mail system is. USPS processes 23.5 million packages per day, and processes and delivers 318 million pieces of mail every day, to every single household in America, 6 days per week (7 days per week for packages).
They will throw mail sacks onto the backs of donkeys and trek them down into the Grand Canyon to deliver to tribes down there. They will deliver by bike, plane, boat, truck, car, etc. Hell, name any other organization where you could hand someone a letter and $0.62 and ask them to take it to Alaska for you, and they'd say no problem.
"Post" roads in the U.S. are named as such because they were roads built specifically for the movement of "post" across the country, and people have even argued that USPS (then the Postal Service) created the layout of the country as we know it.
And despite what many may think or know, USPS is incredibly efficient when it comes to mail and delivery compared to other countries. I remember them telling us during our orientation (I used to be a mail carrier) that back around 2013, representatives from USPS were actually flown to Germany to teach and help them start delivering 6-days per week. USPS taught Germany how to be more efficient at something π