Pinnacle Peak is a 6,562-foot mountain in Mount Rainier National Park in Lewis County, Washington, rising in the Tatoosh Range as its second-highest summit. Distinct from two other Washington peaks of the same name, it is reached by a trail to a saddle and summit known for views of Mount Rainier, though the final climb requires scrambling and some rock climbing. Nearby, The Castle stands about 0.2 miles to the east. The peak lies in a marine west coast climate shaped by Pacific moisture, bringing heavy rain or wet winter snow, while clearer summer weather can improve conditions for this rugged backcountry destination.