In The Shadow of Longs Peak
Button Rock Reservoir
Take Highway 36 from Lyons to County Road 80 (Shelly's Cottage's are at the intersection). Follow County Road 80 about 5 miles as it curves up, down and round the North St. Vrain River. After about 5 miles you will come to a locked gate and ample parking. Unfortunately, one cannot bicycle along this road.
It's an easy 2 mile walk along an access road to Button Rock Reservoir and Ralph Price Dam.
There are a couple of hikes from here too: Sleepy Lion which will also connect into Hall Ranch for a nice thru hike.