Cornwell Reservoir   Be the first to submit input for Cornwell Reservoir. If you have info on Cornwell Reservoir, Valley County, Montana please submit it here to improve this web site.          These outdoors activities are available near Cornwell Reservoir.   Lakes Near Cornwell Reservoir: Forsman Reservoir, Valley County, 10 miles away   Public Lands Near Cornwell Reservoir: Hell Creek State Park, Montana, 37 miles away   Camp Grounds Near Cornwell Reservoir: Trails West Campground, Valley County, 8 miles away