The northern part of Canada before you get into the tundra is one massive contiguous forest 1/3 the size of the United States. It's filled with lakes, streams, rivers, and game - but almost no people. You could easily have small groups of people live there for decades without being discovered. It's so wild that there are places where the wolves have not learned to fear humans.

See a map here (PDF): https://www.nrcan.gc.ca/sites/www.nrcan.gc.ca/files/cfs/asse...