From deer, to elk, to black bear, and even rabbit, hunters like the North Cascades for the wide expanse of territory open to hunting. Except for the National Park, hunting is allowed everywhere else in the North Cascades.
In specific areas of the North Cascades there is a "high hunt", where hunters often use horse-packed base camps and then often use these animals to haul out their kill. Nowadays, where ATVs are allowed in forest service lands outside the National Park, these are also used to haul out fresh kills.
A hunting license is required. The fall hunting season starts on a date set by the the State of Washington. Check with the local U.S. forest service, as well as most outdoor supply and / or sporting good stores.