There are actually hiking trails on both sides of this newly created natural reservoir called Coldwater Lake, and both are excellent starting points and trails to access the limited, but very worthy, backpacking areas in Mount St. Helens National Monument*. This trip report, however, focuses on the rather long but level 10.4-mile, there-and-back day hike on the lake's northern shore. In fact, when visiting the National Monument, the trip along the lake's northern shore, paired with the short Hummocks Loop across Washington Highway 504, make a great introduction to the area.