Mount Thomson is a prominent mountain summit located in the Alpine Lakes Wilderness in eastern King County of Washington state. It's part of the Cascade Range and is a half mile east of the crest of the range. Mount Thomson is situated northeast of Snoqualmie Pass on land managed by Mount Baker-Snoqualmie National Forest. Precipitation runoff on the mountain drains into the Middle Fork of Snoqualmie River. The nearest peak is Alaska Mountain to the southeast, and the nearest higher peak is Chikamin Peak, to the east. The mountain was named for Reginald Heber Thomson (1856-1949), a Seattle city engineer who reshaped the face of Seattle. The first ascent of the peak was made in 1917 by Joe Hazard and B. French.