No permits are required to hike or camp along the OHT. There are registration boxes located along the trail, and it is advised that you sign in at EVERY register that you pass. This helps the forest service know how many hikers are using the trail in order to justify its existence. It also helps track your movements in the case of an emergency – it will be easier to find you. There is no need to put any detailed personal information on the registration cards, like address, phone number, etc.