Boulder-Grand Pass (12,061') spans a broad saddle along the Continental Divide between the Wild Basin Area and East Inlet Valley in Rocky Mountain National Park. An unimproved trails climbs 1500' in 1.45 miles from Thunder Lake to the pass, where you can continue west to Fourth Lake, Spirit Lake, Lake Verna and Lone Pine Lake on a 16.9 mile thru-hike across the Park.

Thunder Lake is located in a broad basin framed by Tanima Peak (12,420') and Pilot Mountain (12,222'); the distinct 'snow triangle' under Boulder-Grand Pass is clearly visible along the Continental Divide

The trail continues along the north side of Thunder Lake to a small meadow and crosses the inlet stream on a short footbridge

The unimproved but well-formed trail clears treeline on a series of short, steep climbs between alpine benches and meadows

Lake of Many Winds (11,610') is located 1.1 miles from Thunder Lake right under Boulder Grand Pass; the snow triangle just below the pass is clearly visible from this point

The route runs counter-clockwise around the lake through large talus to reach steep scree and loose dirt on the far side, where you'll regain a faint path and climb 400' in just .15 miles to the pass

The route leads up the right side of the snow triangle with great views over Lake of Many Winds and Thunder Lake

The route abruptly levels at the pass (12,061'), where you can freely and easily explore vast alpine meadows between Tanima Peak and Pilot Mountain

Looking north from Boulder Grand Pass along the Continental Divide

Meadows slope down and west from the pass with exceptional views of Fourth Lake, Spirit Lake and Lake Verna in the East Inlet Valley

The cross-country route to Fourth Lake drops through flower-covered meadows with navigational clarity to treeline

The forest gradually reconstitutes below 11,000', where travel becomes much more difficult through clutter, deadfall and steep cliffs

Challenging cross-country travel ends in the wide level basin of Fourth Lake, where you'll find an unimproved but well-formed trail along the north shore

Sculpted granite peaks reflect in Spirit Lake along the unimproved trail to Lake Verna

View from thin, beach-like strips on the east side of Lake Verna

The unimproved trail negotiates Verna's rugged shore to pick up the maintained portion of the East Inlet Trail on the lake's west side, where you'll have great views of the route taken from Boulder-Grand Pass to this point

The East Inlet Trail runs by and over several large, scenic pools along Verna's outlet stream

Aerial views over Lone Pine Lake on the descent from Lake Verna

Lone Pine Lake (9,885')

The trail arcs around the north side of East Meadow to the East Inlet Trailhead, an area frequented by elk and moose