How far could a typical person travel in one day in medieval times (or what is the most a person could walk in one day, if they were used to walking a lot, unlike people of today)? I want to know how realistic my estimated distances are in my world, and adjust the story I'm editing as needed (I didn't do a whole lot of research before I wrote it because I wasn't sure what I was writing until I got there).

Figuring the average hiking speed you might use would be between 2 and 3 miles per hour, (going by a little research on serious hikers' websites) that should get you a start. But you also have to make sure you factor in terrain. Over roads or easy terrain like plains of forestlands with minimal undergrowth (i.e. coniferous forests) you can lean toward the upper end of the scale. If you're dealing with rocky terrain or other obstacles like rivers to ford and the like, that's going to slow your traveler down. Weather also counts for the slowdown factor.

The other factor is daylight. If you're dealing with a medieval setting, hiking at night is not going to go well (unless the hiker has some sort of racially enhanced vision or the like. If you've never been away form civilization at night, it is DARK at night to our little human eyes. Like hold your hands out in front of you and try not to bump into stuff dark.) So, on a winter day, you might have as little as 9 hours of good light, or in the summer you'll have more. But you have to use some of that to find and set up camp, of course.

How used to traveling is your character? You say he/she would be accustomed to walking, but walking in town and spending an entire day marching across varied terrain is going to wear on all but those who are used to vigorous all-day travel.

All this to say, going over 20 miles a day might start raising some red flags in the plausibility department. But this IS fantasy, of course. If you can explain, in a way that fits with the rules of your world, something different than "our world" logic, give it a whirl.

Right: Cobha.

I asked myself this question many many times myself. It took me forever to get my distances even okay (and they are still settling). My main character runs practically across a continent on his own at one point, and I was going nuts trying to figure out how long it was. I was very excited when I heard about ultramarathons, therefore. An ultramarathon is a race that is over the regular marathon length of 26 miles, and they can run into the thousands. Suprabha Beckjord was the first person to complete all ten 3100 mile races (he won each one). So it is perfectly possible to stretch things a bit.

I'm going to move this topic to the archives, since I seem to have gotten the answers I needed.