Hi Donna,
Not sure you are still looking for info 14 years later but I may be able to help. I have info on the McMahons from when a few of them left Canada and settled into Wisconsin. (specifically two brothers Joseph and Thomas). I am related to one of the brothers who stayed in Canada but still have a good deal of info about them.

http://familytreemaker.genealogy.com/users/h/i/l/Denice-M-Hi...