Mailbox Peak is an extremely grueling and steep trail. With 4,000 feet in elevation gain in just 2.5 miles, this hike is very difficult. There are great views at the top that only seem improve due to the steepness of the trail. The Old Trail is less maintained than the New Trail and has many more downed trees. The trail starts off with a somewhat gradual grade, but soon the hike starts to pick up and become extremely steep. In many places there are steep steps caused by roots holding the dirt in place. Some of these steps are up to 3 feet tall.
To get to the Old Trail, start by heading up the closed road near the parking lot, following the signs to Mailbox Peak Hike. Soon there will be a trailhead on the left that is for the New Trail. Continue past that for about 0.2 miles, and the Old Trail is on the left with warning signs indicating the trail difficulty.
The trail has reflectors a few feet above eye level on the trees that serve as markers for the trail since the trail gets hard to navigate in places. Eventually the trail will end up meeting with the New Trail, which is clearly marked. From there, the trail opens up and goes through a boulder field. The trail then hugs the ridge all the way up to the summit while maintaining a very steep ascent.
From the summit there are panoramic views of Washington including Mount Rainer, Bellevue, and Seattle from the mailbox. The origins of the mailbox and how it was placed there are still unknown, but the mailbox has gone missing at times only to be replaced by later visitors. The mailbox is a home for food, letters, poetry, and other sundry items that people have brought with them to the summit.