Thirtymile Reservoir   Be the first to submit input for Thirtymile Reservoir. If you have info on Thirtymile Reservoir, Blaine County, Montana please submit it here to improve this web site.          These outdoors activities are available near Thirtymile Reservoir.   Ski Areas Near Thirtymile Reservoir: Bear Paw Ski Bowl, Montana, 66 miles away       900 foot drop, 2 lifts, 25 runs