Where Are the Tunnels in Assassin's Creed 3

AC3 Boston / New York Underground Tunnel Map & Puzzle Solutions

If you're planning on getting full sync in Assassin's Creed 3, completing the underground map is a very good place to start, as they unlock fast travel stations all across Boston and New York. If you're in the last few chapters of the game, or have already finished the story, you'll be able to access every part of the underground.

In order to enter the underground system, you need to look for the entrances, marked by the fast travel icon on your map. They should look something like this:

Once you found the entrance, all you need to do is follow the paths to the other underground entrances around the city. When you find a door, you'll either have to pick lock it open, or complete either a crank shaft or lantern puzzle. Pick locks are easy enough, and crank shafts are pretty easy too. Most of the time you can just spin them around until you find the solution. Lantern puzzles take a little more time; in the room you're in you should be able to find a note. It'll contain clues to the puzzle solution. Or just look below for the solutions I found for you.

Exploring the underground - tips:

-You can completely ignore all of the dead ends; there isn't any bonus for exploring it all, nor are there any hidden chests or items.
-There are also lamps that can be lit throughout the underground system, although they are mostly a waste of time. I only lit the ones in areas that I had to go back to a few times.
-If you see a stone circle on the floor, light the lamp nearby, and the direction you should be going should light up. Eagle vision is also useful when you come to forks in the path.
-There are many obstacles in the tunnels which you'll need to navigate around. Look out for red doors; there should be a nearby powder keg which can destroy them.
-If you open a door, sometimes the fast travel icon won't unlock. Simply go through the door to the surface and it'll unlock.
-Before you enter, make sure you have a lot of ammo!

Boston Tunnels

AC3 - Boston Underground Map

Green Dragon Tavern - Starting point, already unlocked
North Port - Unlocked in sequence 5
Old North Church - crank shaft puzzle
Beacon Hill - pick lock
King's Chapel -crank shaft
Fort Hill -crank shaft
East Fields -pick lock
Crown Coffee House -  magic lantern puzzle :

Crown Coffee House puzzle solution

South Commons - magic lantern puzzle :

South Commons puzzle solution

Boston Gate - magic lantern puzzle :

Boston Gate puzzle solution

New York Tunnels

AC3 - NY Underground Map

South Market - Starting point, already unlocked
Old Dutch Church - pick lock
Bowling Green - Crank shaft - LS right, RS left x2
Brewery - RS right, LS left
City Hall - pick lock
Presbyterian Church - pick lock
East Countryside - pick lock
West Countryside - LS right, RS right, LS right, RS right, LS right
North Dutch Church - magic lantern puzzle :

North Dutch Church puzzle solution

Trinity Church - magic lantern puzzle :

Trinity Church puzzle solution

St. Paul's Chapel - magic lantern puzzle :

St. Paul's Chapel puzzle solution

If anyone has the crank shaft solutions for Boston, please comment below. Good luck navigating these tunnels!

Where Are the Tunnels in Assassin's Creed 3

Source: http://gameguidefaq.blogspot.com/2013/07/ac3-boston-new-york-underground-tunnel.html