The Merrimack Valley Region is an area of south-central New Hampshire, approximately 35 miles wide, centered on the Merrimack River, and running from Canterbury south to the Massachusetts border. Henniker marks the western extent, and Nottingham the east. It includes portions of Hillsborough, Rockingham and Merrimack counties, as well as the state capital of Concord, and the state's largest city: Manchester. Manchester ... boasts a large regional airport, with scheduled, commercial services.