Winter is Coming (asoiaf)

North - 60,000 (can only raise 30,000 in a fast manner)

Riverlands - 40,000-45,000

Vale - 40,000

Iron Islands - 20,000 (their only source of income)

Westerlands - 40,000 (while keeping castles well garrisoned), 50,000 (if left with token garrison as in War of Five Kings.)

Crownlands - 15,000 (5,000 only because of King's Landing)

Reach - 100,000 (60,000 in a fast manner)

Stormlands - 30,000

Dorne - 30,000 - 40,000

Night's Watch - 1,000

North of the Wall - 16,000 (we are talking about army not population)