cohostrail.org:

Welcome to The Cohos Trail …

170 miles of wilderness hiking from southern Crawford Notch in the White Mountain National Forest through the Great North Woods to the Canadian border at far-flung Pittsburg, NH. Hearty souls can then continue on Sentier Frontalier’s trails to Mount Megantic or Mount Gosford in the Eastern Townships of Quebec, Canada. This network is the only international trail system in New Hampshire and the second international pathway in the East. There are many day hike opportunities along the full length of the Cohos Trail and a great deal of remote territory to explore where you may meet more moose than human beings.

Map below from http://nhpr.org/post/where-wild-things-reign-hiking-cohos-trail#stream/0