Mount Adams was the Corps of Discovery's first sighting of the Cascade Range.
October 19, 1805. Clark: I assended a high clift about 200 feet above the water; from this place I descovered a high mountain of emence hight covered with Snow, this must be one of the mountains laid down by Vancouver, as seen from the mouth of the Columbia River, from the course which it bears which is West I take it to be Mt. St. Helens, destant about 120 miles a range of mountains in the Derection crossing a conical mountain S. W. toped with snow....
[This is in fact Mount Adams]
October 19, 1805. Clark: I assended a high clift about 200 feet above the water; from this place I descovered a high mountain of emence hight covered with Snow, this must be one of the mountains laid down by Vancouver, as seen from the mouth of the Columbia River, from the course which it bears which is West I take it to be Mt. St. Helens, destant about 120 miles a range of mountains in the Derection crossing a conical mountain S. W. toped with snow....
[This is in fact Mount Adams]