Map Size: 12:53 minutes from end to end!
How Big is the Map in Assassin’s Creed 3? There are four maps in the game. This is the last map in the game, the map of New York.
I also walked across the other maps in the game. Here are the links to those videos:
Map 1 Boston: https://www.youtube.com/watch?v=KrsSFt80TSE
Map 2 Frontier: https://www.youtube.com/watch?v=UQe4m2TiXBw&t=1502s
Map 3 Davenport Homestead: https://www.youtube.com/watch?v=ByXI4BCg_-Q
(release date: october 2012 / march 2019)
