How Far Can A Man Travel On Foot In One Day Allowing For Food And Rest?

This question depends upon so many factors.  Presuming that the ground is flat and there are no obstacles, a human being can walk at between 3 and 5 mph.  Within one day, a person could travel anywhere between 3 mile and twenty four hours x three-five miles. It is unlikely that the person will keep a standard pace.

It is also unlikely that the person will walk for more than eleven hours and it is probably best for the person to stop for a break for at least two of those eleven hours.  

So, if the average speed is four miles per hour and the ground is flat and there are no obstacles to prevent progress and the person walks for a reasonable nine hours per day, then that person will walk for roughly thirty six miles per day.  

Obviously, the factors of weather, walking speed, terrain and obstacles play a major factor in the answer to this question, however thirty six miles seems a good journey in one day.