1 Answer

Every mile was covered at a full gallop.

A horse will walk 3-4 mph, trot about 8-10 mph and gallop depending on the ability of the animal and the terrain at 30-40 mph. According to the U S Cavalry a horse can cover some 30-40 miles a day but can be pushed to double that but then will be pretty much spent for several days while he recuperates. The US Cavalry mounted service cup race averaged 60 miles a day for five days carrying a rider and over 200 pounds of gear. A Pony Express rider would cover 75-100 miles on their portion of the mail run and would change horses at way stations every 10-15 miles. The entire 2000 miles of the trail would be covered in 10 days with riders riding 24 hours a day. That makes an average of about nine miles an hour according to express records, but daylight riders did much better and night riders moved much slower. By means of comparison modern racehorses have achieved records up to 40 mph.

http://www.janabommersbach.com/tw-mag-ponyexpress.php

http://www.terryburns.net/How_fast_could_they_travel.htm