lol terrorizing . chill out . sounds like their parents are just informing them that we have a president now that ' s a bauce . and is going to put his foot down when it comes to being here illegally . <| sep |> The population estimate is based on Scotland of 12001300 CE extrapolated to the Wikki and community estimates of the size of Westeros and the North . As such , the North at the time before the War of the Five Kings would have around 10 million people and all of Westeros , somewhere between 70 and 80 million . The estimated average number of males would be somewhere around 5 million . The number of males between 15 and 55 , which could be mobilized would be somewhere around 2 million . The optimal military age of population of males between 17 and 35 would be around a million . Certainly , such numbers couldn ' t be mobilized at the same time as I indicated , 300 , 000 would be the maximum one could concentrate in a reasonable time in one location , say the west coast against the Ironborn , the Neck against the South or the Wall against the WWs . 25 , 000 to 50 , 000 would be the maximum for an expedition south of the Neck or an invasion of the Iron Islands or north of the Wall , which is close to the size of the army Robb Stark lead into the River Lands . Again this a first order analysis of MAXIMUM numbers . Such numbers would be affected by a number of factors . Harald could only raise 7 , 000 men for Hastings with his and the local thegns ' Huscarls and the fyrd levy of all free men , but this would have increased to 10 , 00012 , 000 in a few days as the local troops farther away from the scene of the battle answered his summons . This when England had a population of between 1 . 5 and 2 . 5 million , which would put all males at . 75 to 1 . 25 million , all males available for mob at 375 to 660 thousand and optimal military population at 180 , 000 to 330 , 000 for the entire Kingdom . Given the population density , the transportation and communications network , the political and economic situation in southwest England , mobilizing 12 , 000 troops in a week was to be expected and had Harald had the political flexibility to fall back toward ' s London , he might have had 2030 , 000 troops to face William of Normandy . So I don ' t think my numbers are far off for the North . The Carolingian Empire was in the early medieval period . Westeros is obviously somewhat more advanced than Europe in the late Dark Ages . Thus my use of population estimates for the High Middle Age . Again , my estimates are of maximum military capability , not the optimal or actual probable size of the armies that could be mobilized , commanded and sustained in a fantasy world mixing elements of Medieval Europe from Norway to Spain and from the end of the Dark Ages into the early Renaissance periods . In any case , GRRM writes fantasy not military history , so we just have to go with flow sometimes .