Elk Poop Mountain, oops I mean Observation Peak is located between Mounts Saint Helens and Adams in the Trapper Creek Wilderness which lies within the Gifford Pinchot National Forest. Observation Peak offers exceptional views of the above volcanoes. Views stretch also along the Cascade crest from Rainier in the north to Jefferson in the south. This peak is a former lookout site, hence the name. The lookout was destroyed in the 60's but the bare summit still has the views.
There are no less than 5 options for getting to the summit ranging from the Big Hollow Trail with 2700 feet of elevation gain to various trails up Howe RIdge with about 3200 feet of gain. The Howe Ridge and Trapper Creek hikes are between 13.2 and 14.4 miles round trip while the Big Hollow Trail is 9 miles round trip. (Note that the Big Hollow Trail involves a creek/small river crossing that can be impassable early in the year in high water.)
The forests you hike through are amazing. Filled with waterfalls, creeks, flowers and huge old-growth trees, you don't really notice there are no big views until you get near the summit. Some of these firs must approach 300 feet tall. There are also huge hemlock and cedar specimens. Elk also abound (as you can guess from the statement above). Came across a group of 5 very near the trailhead that elevated ("effortlessly scaled" doesn't really do these amazing beasts justice) the ridge in front of us once we were heard.
This peak is about an hour and a half from Portland and is well worth the trip if you enjoy monster trees, waterfalls and great views of the Cascade giants. All routes are just hikes but from what I have seen, the masses and crowds have not really discovered this area. Never seen another soul on it. Of note also is that this area of Washington in the Wind River Ranger District can be its own microclimate and receive healthy dumpings of snow when similar elevations are bare.