Fodor's Expert Review Monadnock State Park

Said to be America's most-climbed mountain—more than 400 people sometimes crowd its bald peak—Monadnock rises to 3,165 feet, and on clear days you can see the Boston skyline. When the parking lots are full, rangers close the park, so it's prudent to make a reservation online or get a very early morning start, especially during fall foliage. Five trailheads branch out into more than two dozen trails of varying difficulty (though all rigorous) that wend their way to the top. Allow three–five hours for any round-trip hike. The visitor center has free maps as well as exhibits documenting the mountain's history. In winter, you can cross-country ski along roughly 12 miles of groomed trails on the lower elevations. Pets are not permitted in the park.