The total distance covered by a horse in a day will be determined largely by the pace that you set for the ride. A horse's speed depends on gait:
Walk: 4 mph
Trot 8 to 12 mph
Canter 12 to 15 mph
Gallop 25 to 30 mph
A typical horse may be comfortable walking for eight hours, meaning he could cover 32 miles in that time. Many weekend-warrior riders can't stand eight hours in the saddle, though. A more fit horse may cover more distance if he is able to trot or canter for part of the time.