Покопался с помощью гугл переводчика на англоязычных форумах. Та многие население Севера вообще в 6 млн определяют. Интересны раскладки по городам и Эссосу, хотя со многим не согласен.
Westeros: 40,000,000 (Confirmed)
Regions
-North: 4,000,000
-Reach: 10,000,000
-Westerlands: 7,000,000
-Iron Islands: 1,000,000
-Dorne: 2,500,000
-Crownlands: 1,500,000
-Vale of Arryn: 5,000,000
-Riverlands: 5,000,000
-Stormlands: 4,000,000
-Beyond the Wall: 150,000
Cities and towns
-King's Landing: 500,000 (confirmed)
-Oldtown: 450,000
-Lannisport: 250,000
-Gulltown: 200,000
-White Harbor: 100,000
-Barrowton: 30,000
-Lord Harroway's Town: 40,000
-Duskendale: 60,000
-Ashford: 80,000
-Grassy Vale: 40,000
Essos west of the Bone Mountains: 42,330,000
Free Cities
-Braavos (city): 900,000
-Braavos (country): 2,500,000
-Lorath (city): 250,000
-Lorath (country): 1,000,000
-Pentos (city): 800,000
-Pentos (country): 2,500,000
-Myr (city): 700,000
-Myr (country): 2,000,000
-Tyrosh (city): 600,000
-Tyrosh (country): 1,700,000
-Lys (city): 600,000
-Lys (country): 1,700,000
-Norvos (city): 600,000
-Norvos (country): 2,500,000
-Qohor (city): 700,000
-Qohor (country): 1,700,000
-Volantis (city): 1,000,000
-Volantis (country): 4,000,000
-Selhorys: 80,000
-Valysar: 150,000
-Volon Therys: 200,000
Dothraki Sea: 4,000,000
Saath: 200,000
Slaver's Bay and Ghiscar
-Mantarys (city): 150,000
-Mantarys (country): 500,000
-Tolos (city): 250,000
-Tolos (country): 1,000,000
-Meereen (city): 600,000
-Meereen (country): 3,000,000
-Astapor (city): 300,000
-Astapor (country): 1,500,000
-Yunkai (city): 250,000
-Yunkai (country): 1,300,000
-New Ghis (city): 800,000
-New Ghiscar: 3,300,000
Lhazar: 3,500,000
Qarth (city): 1,500,000
-Qarth (country): 4,000,000