Merrimack County, New Hampshire

Merrimack County is a county in New Hampshire, United States, centred on the state capital of Concord, in the south-central part of the state. It had a population of 153,808 at the 2020 census and covers 955 square miles (2,473 km2) centred near 43°20′N 71°41′W.

Concord is the county seat, and its postal code is 03301. The county has 2 cities and 25 towns, plus a handful of unincorporated villages and census-designated places inside those towns. Merrimack County is in the Eastern time zone.

Towns & Villages in Merrimack County

Merrimack County’s 27 municipalities split into 2 cities — Concord and Franklin — and 25 New Hampshire towns, the state’s basic form of local government. Several towns also contain older mill villages and census-designated places (CDPs) that have their own name and post office but no separate government; those are listed below as Village or CDP. Population figures are 2020 census counts; a dash means no verified figure for that specific place.

Two villages carry the “South” prefix in Sutton and Newbury; both sit a few miles from their town’s main settlement and are best found by the town name on a map, not the village name alone. Penacook, Contoocook and Suncook are the county’s three historic mill villages, each built around a 19th-century water-powered textile or paper mill on the Contoocook, Warner or Suncook River.

ZIP Codes

• 03301 — Concord (also serves East Concord and West Concord)
• 03303 — Concord PO boxes (also covers Penacook)
• 03106 — Hooksett
• 03275 — Suncook (also serves Allenstown and part of Pembroke)
• 03235 — Franklin
• 03304 — Bow
• 03242 — Henniker
• 03229 — Contoocook (also serves Hopkinton)
• 03307 — Loudon
• 03234 — Epsom

Most of the county’s smaller towns and villages, including Andover, Boscawen, Bradford, Canterbury, Chichester, Danbury, Dunbarton, Hill, New London, Newbury, Northfield, Pittsfield, Salisbury, Sutton, Warner, Webster and Wilmot, share ZIPs with a nearby post office town or use their own that a mail carrier assigns; check a specific address against the USPS ZIP lookup rather than the town name alone.

Geography

Merrimack County straddles New Hampshire’s Merrimack River valley. The eastern towns — Concord, Bow, Hooksett, Pembroke and Allenstown — sit in the flat, sandy river terraces that run down the middle of the state; the western towns climb into the foothills below Mount Kearsarge and Mount Sunapee, where Bradford, Sutton, Warner and Newbury border the Sunapee-Kearsarge highlands. The Contoocook River, the Merrimack’s largest tributary in the county, flows north to south through Hopkinton, Concord and Boscawen before joining the Merrimack. Newbury shares the northeastern shore of Lake Sunapee with neighboring Sullivan County.

Merrimack County borders Belknap County to the northeast, Strafford County to the east, Rockingham County to the southeast, Hillsborough County to the south, Sullivan County to the west, and Grafton County to the northwest.

Demographics

Merrimack County had 153,808 residents at the 2020 census, New Hampshire’s third-most-populous county. Concord (43,976) and Hooksett (14,871) are its two largest communities, together holding more than a third of the county’s population. Median household income runs close to the New Hampshire median of $96,838, with Concord’s suburban towns — Bow, Hopkinton and Dunbarton — among the higher-earning towns in the county and its rural western towns generally below the state figure. Population density is roughly 165 people per square mile of land.

Economy & Local Life

Concord’s role as New Hampshire’s capital, home to the State House, the legislature and most executive-branch agencies, makes state government the county’s largest single employer. Concord Hospital, the largest hospital in the region, and several insurance and financial-services firms headquartered in Concord add to the white-collar employment base. Franklin and Penacook keep a smaller manufacturing base rooted in the county’s old paper and textile mills. Away from the Concord area, the western towns around New London and Sutton lean on tourism tied to Lake Sunapee, Mount Kearsarge and Mount Sunapee’s ski area, plus dairy and produce farms that supply Concord’s weekly farmers’ markets.

History

Merrimack County was organized in 1823 out of towns split off from Hillsborough and Rockingham counties, and takes its name from the Merrimack River, an Abenaki word generally translated as “swift water” or “strong place.” Concord had already been the state’s permanent capital for several years by then, chosen in part for its central location on the river. Canterbury, in the county’s northeast corner, is home to Canterbury Shaker Village, founded in 1792 and one of the longest-continuously-run Shaker communities in the United States before its last members died in the 1990s; the site is now a museum.

Getting There

Interstate 93 runs north-south through Concord, Bow and Hooksett, the county’s main commercial corridor, while Interstate 89 crosses the western towns through Warner and Sutton on its way toward Sunapee and Vermont. U.S. Route 3 and New Hampshire Routes 4, 9 and 106 connect the smaller towns to Concord.

• Manchester — 18 miles south
• Boston, Massachusetts — 70 miles south
• Portsmouth — 45 miles east
• Hanover — 45 miles northwest

Manchester-Boston Regional Airport, about 15 miles south of Concord in neighboring Hillsborough County, is the nearest commercial airport.

Frequently Asked Questions

Where is Merrimack County, New Hampshire?
It sits in south-central New Hampshire, along the Merrimack River, around the state capital of Concord.

What is the population of Merrimack County?
153,808 people, as of the 2020 census, making it New Hampshire’s third-most-populous county.

How big is Merrimack County?
955 square miles (2,473 km2), of which about 22 square miles is water.

What is the county seat of Merrimack County?
Concord, which is also the New Hampshire state capital.

How many towns and cities are in Merrimack County?
27 — the cities of Concord and Franklin, and 25 towns.

What ZIP codes are in Merrimack County?
Major ZIPs include 03301 and 03303 (Concord), 03106 (Hooksett), 03275 (Suncook/Allenstown), 03235 (Franklin) and 03304 (Bow); smaller towns use their own or a neighboring post office’s ZIP.

What is Canterbury Shaker Village?
A former Shaker religious community founded in 1792 in Canterbury; it operated for two centuries and is now a museum open to the public.

More counties in this state: Towns and villages in New Hampshire.