Southwestern and south-central New Hampshire mix village charm with city hustle and bustle across two distinct regions. The Merrimack River Valley has the state's largest and fastest-growing cities: Nashua, Manchester, and Concord. To the west, in the state's sleepy southwestern corner, is the Monadnock region, one of New Hampshire's least developed and most naturally stunning parts. Here you'll find plenty of hiking trails, as well as peaceful hilltop hamlets that appear to have barely changed in the past two centuries. Mt. Monadnock, southern New Hampshire's largest peak, stands guard over the region, which has more than 200 lakes and ponds.