Located in northern Montana, Glacier National Park is rugged.  Its only road is called Going to the Sun, and runs east-west between St. Mary's Lake and Lake McDonald, over several significant mountains.  Unfortunately, the glaciers are receding and may eventually disappear.  Grizzly bears are plentiful - many of them have been relocated here from Yosemite and other parks because of their bad behavior around tourists.  Glacier is definitely worth your visit, and offers numerous hikes as lake activity.