See: http://www.libbymt.com/areaattractions/libbycreekgold.htm
Take Libby Creek road off of Hwy 2 about 13 miles south of Libby. Bear (no pun) left at the Bear Creek intersection about 1/2 way. You will cross Libby Creek 3-4 times. Look for the public gold panning signs. Turn left over Libby Creek after you see the sign. Public area is on the right soon after crossing the creek.