This is not a great classic western,, but it is one of those rare stories set in the pre 19th century North America. MOHAWK succeeds in celebrating some of the beauty of the culture and costume of First Nation, Amer-Indian peoples but the story, of course, is hocum. Be realistic, what would you expect from '50's Hollywood ?. It's a romance with the usual sort of 'frontier' violence. Most of the big action shots are taken from an earlier picture but they are matched fairly skillfully. This works well as entertainment. If you don't dig it, leave it.
The colonial period, for sure, was not all genocide but if you want some thing like real history you'll have to look at Kevin Annet's, 'Un-repentant' or his book,'Hidden from History'.
By the way, you'll have to be very watchful if you are going to spot young actors such as: Duvall, Berenger and Harris in MOHAWK.