i only found one in NY and 2 so far in boston

You can get 1 more in boston and 2 more from NY then. You'll get an achievement when you liberate all 3 sections of one of the cities too

from the map it says

boston south district
controlled---------disputed 71%
contact-----------flipper wilkinson

boston central district
control--------liberated


boston north central
control-------------disputed 71%
contact ducan litle


i dont see any more liberation mission tho

You probably have unexplored areas, which is what I had. Look for viewpoints or just go to parts of the map you haven't been and you'll run across something

well i have all veiw points unlocked

I did too in both cities but there were still unexplored parts which is where I found at least 3 missions

awh i just found liberation mission on a explored area

hmm i went around north district in boston 3 times and i cant find the last liberation mission

I think north boston is where you beat up merchants? Unless it's different

from what i look up it say one mission is Stop thugs harassing the merchants [0/3]

i did see one guy flee
so can i kill the guy that flees?
or do i tackle them?

http://www.ign.com/wikis/assassins-creed-3/Liberation_Missions