From Peak Bagger: Ruby Mountain, also known by some people and resources as Ruby Peak, is a significant mountain in the North Cascades region of Washington. Perhaps most notably to peakbaggers, with 3888' of clean prominence Ruby Mountain is the 21st-most prominent peak in Washington.
The up route is to be started at colonial camp ground, then on thunder creek trail, up fourth of July pass, and turn on the climbers trail at the sign. Once the trail ends, follow the gulley to the top and hit the official summit at the radio towers.