Tatoosh Peak is a 6,310-foot mountain summit in Lewis County of Washington state. It is part of the Tatoosh Range which is a subrange of the Cascade Range. It is the highest point in the Tatoosh Wilderness, a protected area which is managed by Gifford Pinchot National Forest. The name tatoosh derives from Chinook Jargon which means breast. Preā¦Tatoosh Peak is a 6,310-foot mountain summit in Lewis County of Washington state. It is part of the Tatoosh Range which is a subrange of the Cascade Range. It is the highest point in the Tatoosh Wilderness, a protected area which is managed by Gifford Pinchot National Forest. The name tatoosh derives from Chinook Jargon which means breast. Precipitation runoff from the peak drains into tributaries of the Cowlitz River.