The East Portal Trailhead, which sits just outside of Rocky Mountain National Park, provides access to Emerald Mountain, the Wind River Trail, the Storm Pass Trail, Glacier Basin and two summits that are not named on any map, but are unofficially known as Thunder Peak and Lightning Peak.
This trailhead is at the eastern terminus of the Alva Adams Tunnel, which diverts water from Grand Lake on the western side of the Continental Divide to the thirsty cities on the Eastern plains.
There are no restrooms or potable water at this trailhead.
To get to the East Portal trailhead from the junction of US 36 and CO 66, just west of Estes Park, head 3.3 miles southwest going past the YMCA of the Rockies on CO 66 till it ends at a circular loop where there is limited parking. Another alternative to getting to this trailhead is by taking the free Estes Park shuttle
bus via the Brown Route, during the summer season.
From the parking area start walking west, and go around the gate that blocks the road that heads on up towards the small reservoir by the portal. This roadway use to be open and you could park closer to the actual trail but in the wake of 9/11 this last part of the road was blocked off.
From the pool the trail, depending on where you are going, either follows along the north shore of the pool and then continues up the Wind River, or heads up the slope to the north of the pool. The second trail heads towards Emerald Mountain and Glacier Basin Campground.