User blog comment:Slate Vesper/Assassinews 15-06-'13 — Three Assassin's Creeds in development and Patrice Désilets' lawsuit with Ubisoft/@comment-4999424-20130629131040/@comment-4829046-20130629142657

Considering that you can chase a person from a city right into the open ocean without loading screens or cutscenes, yes it is one big map.