Armstrong Mountain rises to 4,400 feet as the 22nd-highest of the Adirondack High Peaks, a prominent shoulder of the Great Range above Keene Valley. The peak takes its name from Thomas Armstrong, a Plattsburgh lumberman who purchased the surrounding land in 1866 and named the mountain for himself three years later. The earliest recorded ascent came in 1875. Today the approach runs through Adirondack Mountain Reserve land, where dogs are not permitted and a free parking reservation is required from May 1 through October 31.
The standard route begins at the Garden Parking Lot in Keene Valley, follows the Phelps Trail to a DEC Interior Outpost at 3.1 miles, then picks up the ADK Range Trail over Upper Wolfjaw before continuing to Armstrong's summit, a 7.0-mile one-way journey with roughly 2,500 feet of total elevation gain. Fixed ladders and cables assist on the steepest sections. An alternative line climbs from the Ausable Club via the Lake Road and Beaver Meadow Trails.
The summit opens to views of Johns Brook Valley and the ridgeline sweep of the Great Range. Armstrong is most often tagged as part of a longer traverse pairing it with Upper and Lower Wolfjaw, or as a stop on a full Great Range traverse. The exposed ridge demands careful route-finding in icy conditions, and hikers should be prepared for technical terrain in early spring and late fall.
