Merrimack is a town in Hillsborough County, New Hampshire, United States. The population was 25,494 at the 2010 census, and an estimated 25,660 in 2017, making it the ninth-largest municipality in New Hampshire.
According to the United States Census Bureau, the town has a total area of 33.4 square miles (87 km), of which 32.6 sq mi (84 km) is land and 0.8 sq mi (2.1 km) (2.48%) is water. The highest point in Merrimack is an unnamed hill in the northwestern part of town that reaches 512 feet (156 m) above sea level.
As of the census of 2010, there were 25,494 people, 9,503 households, and 7,150 families residing in the town. There were 9,818 housing units, of which 315, or 3.2%, were vacant. The racial makeup of the town was 95.0% white, 0.8% African American, 0.2% Native American, 2.0% Asian, 0.02% Native Hawaiian or Pacific Islander, 0.5% some other race, and 1.6% from two or more races. 2.1% of the population were Hispanic or Latino of any race.
Of the 9,503 households, 36.7% had children under the age of 18 living with them, 62.6% were headed by married couples living together, 8.5% had a female householder with no husband present, and 24.8% were non-families. 18.8% of all households were made up of individuals, and 5.7% were someone living alone who was 65 years of age or older. The average household size was 2.67, and the average family size was 3.06.
In the town, 24.5% of the population were under the age of 18, 6.7% were from 18 to 24, 25.7% from 25 to 44, 32.7% from 45 to 64, and 10.3% were 65 years of age or older. The median age was 40.7 years. For every 100 females, there were 99.0 males. For every 100 females age 18 and over, there were 96.4 males.
For the period 2011-2015, the estimated median annual income for a household was $90,708, and the median income for a family was $101,786. Male full-time workers had a median income of $69,937 versus $50,184 for females. The per capita income for the town was $39,695. 4.0% of the population and 2.3% of families were below the poverty line. 4.7% of the population under the age of 18 and 4.4% of those 65 or older were living in poverty.
Merrimack New Hampshire neighborhoods include: Bowers Landing, Cambridge Dr, Camp Sargent Coop, Castleton Ridge, Country Crossing, Cramer Hill, Crosswoods Path, Daniel Webster – Hilton, Front Street, Greater Wire Road, Greenfield Farms, Lamson, North Merrimack, Parkhurst, Sidewalks are missing, The Birches, Thorntons Ferry, Woodland Dr