Dirtybox Peak is the unofficial name for the largest peak on the ridgeline containing Mailbox Peak and Dirty Harry's Peak. In fact, the nickname "Dirtybox" was originally derived from combining the parts of names from the mountain's more famous neighbors: Dirty Harry's Peak and Mailbox Peak. Dirtybox Peak is also known as "Peak 4926" and "Mount Defiance - West Ridge Peak".
With Dirtybox Peak being located between Mailbox Peak and Dirty Harry's Peak, and being taller than both, Mailbox Peak cannot be seen from the summit of Dirty Harry's Peak, and vice-versa. Yet, despite this distinction, Dirtybox Peak is seldom visited by hikers and its summit routes remain rugged. In contrast, Mailbox Peak and Dirty Harry's Peak are very popular hiking destinations with well-defined summit routes.
There are three main approaches for Dirtybox Peak. The most popular approach is the northwestern approach, which follows a ridgeline from Mailbox Peak and ranges from YDS Class 2 to Class 3. Another approach is the southeastern approach, which follows a ridgeline from the summit of Dirty Harry's Peak, passes a smaller unnamed peak, and ranges from Class 2 to Class 3. Yet another approach is the northeastern approach, which originates from the now-defunct Granite Creek Road around the north sides of Mailbox Peak and Dirtybox Peak, then follows an old logging road up the eastern slopes of Dirtybox Peak to 4200' elevation before bushwhacking to the summit, and is basically Class 2 but is a very long route for this mountain.
Driving Directions For Most Popular Approach (From Mailbox Peak):
1) Follow I-90 until several miles east of North Bend, Washington.
2) Take Exit 34 (468th Ave. SE). Head north.
3) After 0.6 miles, turn right onto SE Middle Fork Road.
4) After 0.9 miles further, the road splits. It does not matter which side to choose, as both roads rejoin 1.0 mile further.
5) The Mailbox Peak Trail parking area is approximately 0.25 miles after where the roads rejoin each other. A blue gate is on the rightside of the road, marking the entrance to the route.