Mail Drops in Maine and NH

[The Mouth]

I'm starting my thru hike in Maine in early July, I have to carry medication, so I need a reliable system of mail drops to keep up to date, I will carry an emergency supply just in case, however, I was wondering where the best and most reliable mail drops are in Maine and New Hampshire. Any information would be very welcome. Thanks!

[Slo-go'en]

Your guide book lists all the PO along the trail, which also happen to be in all the towns you pass by or through. In some places you can mail to a business, hostel or motel (sometimes with a fee). Exactly which ones you use will depend on several factors which only you can determine.