Views of Mount Rainier on clear days and wildflowers in the summer.
The Mailbox Peak hike is very popular since it is less than an hour's drive from Seattle. The first two hours (4 miles) of the trail are long switchbacks inside the shady, cool forest.
After leaving the forest, there is a large boulder field with easy steps that wind up through the rocks. It's hard to see the rock path from below but once you are on it it's easy to follow.
After the boulders, the trail gets a lot steeper and it is slow going for about 20 more minutes to the mailbox. The mailbox is adorned with stickers, graffiti and many things that people have left both inside it and around it. Don't forget to check the mail.
From the top, on clear days, there are epic views of Mount Rainier to the South.