North - 60,000 [can only raise 30,000 in a fast manner, (North could have raised 40,000 in show as well but could only call 20,000 in the time they had, but now the North was better managed and fought less wars, not participated in any Blackfyre rebellion, which increased the population)]
Riverlands - 40,000-45,000
Vale - 40,000 (could have called another 10,000 but they have to leave some behind to deal with mountain clansmen)
Iron Islands - 20,000 (their only source of income is piracy means they need more men as they constantly lose them and have no shortage of women for bearing them)
Westerlands - 40,000 (while keeping castles well garrisoned), 50,000-60,000 (if left with token garrison as in War of Five Kings.)
Crownlands - 15,000 (5,000 from King's Landing alone)
Reach - 100,000 (60,000 in a fast manner)
Stormlands - 30,000
Dorne - 30,000 - 40,000
Night's Watch - 1,000 (if working at max than 10,000, which has not happened since conquest)
North of the Wall - 20,000 (we are talking about army not population)