Big Cheif Reservoir   Be the first to submit input for Big Cheif Reservoir. If you have info on Big Cheif Reservoir, Natrona County, Wyoming please submit it here to improve this web site.          These outdoors activities are available near Big Cheif Reservoir.   Whitewater Near Big Cheif Reservoir: Powder River - Middle Fork, Washakie JohnsonCounty, 13 miles away       Class II-V - 12 miles long (Forest Service Road bridge Close to county line to Highway 190)