Mount Desert Island and Acadia National Park are the premier destinations for bikers, especially mountain bikers who want/prefer easy-riding terrain -- the cycling here may be some of the most pleasant in America. Its 57 miles of well-maintained national-park carriage roads offer superb cruising through thick forests and to ocean views atop rocky knolls. No cars are allowed on these grass and gravel lanes; bikers and walkers have them to themselves. You can rent mountain bikes in Bar Harbor, which has at least three bike shops. The Park Loop Road, while often crowded with slow-moving cars, offers one of the more memorable road-biking experiences in the state. The rest of Mount Desert Island is also good for highway biking, especially on the quieter western half of the island, where traffic is almost never a problem.
Also, don't overlook the islands for relaxed biking. In Casco Bay, Chebeague Island offers a pleasant wooded excursion. Vinalhaven and North Haven in Penobscot Bay and Swan's Island in Blue Hill Bay are also popular with bikers.
Plenty of serious mountain biking is available for those who like to get technical on two wheels. Your best bet is to consult area bike shops for the best trails, which are typically a matter of local knowledge.
The Maine Department of Transportation publishes a booklet, Explore Maine by Bike, describing 25 popular bike trips around the state; log onto www.exploremaine.org/bike to get it. The Maine DOT also publishes a map marked up with state biking information, including traffic volumes and road shoulder conditions along popular routes. You can order it by e-mailing bikeinfo@maine.gov or by calling the DOT at tel. 207/624-3252.