In 'Game of Thrones' and its sequels, George R R Martin refers to places as being hundreds or even thousands of leagues apart. I thought a league was three miles, but if so, his characters are travelling around really fast. Is he using 'league' for 'mile'?
Yes, a league is three miles.
I have deliberately tried to be vague about such things, so I don't have obsessive fans with rulers measuring distances on the map and telling me Ned couldn't get from X to Y in the time I say he did.
However, if you really must know, you can figure out the distances for yourself. The Wall is a hundred leagues long. A league is three miles. Go from there.
But if you turn up any mistakes in travel times by using that measure, let it be your secret.
Shhh! We won't tell if you don't!
George R. R. Martin says that events aren't written chronologically and the chapters happen in a day or a month or a year... So it's not that these characters are all over the place in a short time frame because you never really know how long journeys take unless the author flat out tells you. Also, sometimes the characters back track or have to deal with some sort of issue so they might take longer to get from point A to point B.
In addition to Gilles' answer; there is proof in the books that a league is roughly equal to three miles.
From A Dance With Dragons:
“One hundred leagues from Deepwood Motte to Winterfell,” said Artos Flint, the night the argument boiled to a head in Galbart Glover’s longhall. “Three hundred miles as the raven flies.”
-A Song of Ice and Fire: A Dance With Dragons, Part One - Dreams and Dust, Chapter Fourty-Two (The King's Prize).
The league originally referred to the distance that a person could walk in one hour. The English league is indeed 3 miles, but there was no global standard and as such the league has fallen out of use as a unit of measurement. As far as I know, no definitive standard has been set for what a league actually is so I would personally go with the simplest which is the distance a person can walk in one hour.
Jon Snow says the distance from the wilding camp to Dorne is 10,000 leagues. At 30,000 miles, that's longer than the earth's circumference. If this is really the War of the Roses and set in England (Yorks v Lancasters), then it's more like 1/10 mile per league, but then that doesn't work for the wall which should be hundreds of miles long. So I take the answer to be that GoT is 8,000 pages and keeping the distances correct was out of our league....
A league is 3 miles as many posts have pointed out in ADWD Stannis is 100 leagues or 300 miles from Winterfell. The understanding of that distance is how far the average person walks in an hour (humans average 3 miles per hour)
We don't really know how fast characters are traveling though it may be safe to say that the most anyone travels in a day is about 10 leagues (30 miles). A horse on a flat or gently rolling terrain has a max of 40 miles in a day and well most terrain isn't ideal and most of our characters tend to be moving around on foot a lot.
As for some of the "thousands of leagues" that get mentioned those could be an expression for "really F###ing far" or it could be that the distances aren't surveyed measured out but are rather given in terms of travel time. A really steep hill that is only a mile in true distance might be given a greater distance in the way that characters perceive the distance.
if 1000 leagues =3452 miles. there is no way you can do that in a week. Hell you'd have a hard timed doing that today, horses cannot maintain full speed for 8 hrs. 4 mph for 8 hours is better bet. even then, lost shoes, coming up lame, broken wagon wheels, and everything else that can go wrong. but just for the sake of argument lets say they make an average of 4 mph per day and have a 12 hr day each day. 3452/4= 863 hours travel. 863/12= 72 days on the road. thats a best case scenario it will probably get stretched out a 4 to 6 months.