Three miles after exiting Rocky Mountain National Park
, the Colorado River is impounded to form two reservoirs, both (plus another three) contained within Arapaho National Recreation Area
. The first is Shadow Mountain Lake
, accessible in a few places from US 34 which runs all along the west shore, though much of the land along this section of the water's edge is privately owned. The far side of the lake is much less easily reached, bordered by steep slopes at the edge of the mountains of the national park.
Arapaho National Recreation Area - full description