Hidden Lake is in Glacier Natinal Park. The name of the pass is slipping my mind, but it's an amazing place! The hike into it is pretty amazing too. But before you go check on the bears, and the weather.
Hidden Lake is just on the edge of the Blackfoot Indian Reservation if I am not mistaken. Within an hour and a half you can be at Duck Lake, Kipp Lake, Mission Lake, Hidden Lake, McGee Lake, etc. Warning: if you bring your tube, be prepared for the wind. It can be gorgeous at 8:00 am and the next thing you know you're fighting whitecaps while you scramble back to shore.