Maine is home to 10 peaks over 4,000 feet and hundreds of miles of maintained trails. Acadia National Park has wonderful day hiking, though its trails can be crowded during the peak summer season. In western Maine, 50,000 acres of the White Mountains spill over New Hampshire's border and boast an excellent network of trails. Pathways in and around Evans Notch and Grafton Notch (both easily reached from Bethel) offer trails for hikers of all levels. Finally, Bigelow Range, near the Sugarloaf/USA ski resort, offers challenging trails and stunning vistas from high, blustery ridges. The Appalachian Trail traverses the range on its way from Grafton Notch to the trail's terminus at Mount Katahdin; a good source of trail info is the Appalachian Trail guide.
Two guides to the state's trails are highly recommended. 50 Hikes in Southern and Coastal Maine, by John Gibson, is a reliable directory to trails at Evans Notch, Acadia, and the Camden Hills area. 50 Hikes in the Maine Mountains, by Chloe Chunn, is the best guide for the Bigelow Range and Baxter State Park. Both are published by Backcountry Publications and are available at local bookstores or online.