Threemile Reservoir   Be the first to submit input for Threemile Reservoir. If you have info on Threemile Reservoir, Blaine County, Montana please submit it here to improve this web site.          These outdoors activities are available near Threemile Reservoir.   Ski Areas Near Threemile Reservoir: Bear Paw Ski Bowl, Montana, 73 miles away       900 foot drop, 2 lifts, 25 runs