Middleton is a town in Strafford County, New Hampshire, United States. The population was 1,783 at the 2010 census.
According to the United States Census Bureau, the town has a total area of 18.5 square miles (48 km), of which 18.1 sq mi (47 km) is land and 0.4 sq mi (1.0 km) (2.27%) is water. That water is primarily contained by Sunrise Lake, previously known as the Old Dump Reservoir. The Moose Mountains, which separate Middleton from Brookfield, have a series of 1,600-to-1,700-foot (490 to 520 m) peaks, including the highest point in Middleton at an elevation of 1,670 feet (510 m) above sea level.
The town is served by New Hampshire Route 153.
As of the census of 2000, there were 1,440 people, 514 households, and 389 families residing in the town. The population density was 79.6 people per square mile (30.7/km²). There were 706 housing units at an average density of 39.0 per square mile (15.1/km²). The racial makeup of the town was 98.54% White, 0.14% African American, 0.21% Native American, 0.56% Asian, and 0.56% from two or more races. Hispanic or Latino of any race were 0.35% of the population.
There were 514 households out of which 38.1% had children under the age of 18 living with them, 63.0% were married couples living together, 6.6% had a female householder with no husband present, and 24.3% were non-families. 16.5% of all households were made up of individuals and 3.9% had someone living alone who was 65 years of age or older. The average household size was 2.80 and the average family size was 3.13.
In the town, the population was spread out with 28.8% under the age of 18, 6.5% from 18 to 24, 34.1% from 25 to 44, 20.3% from 45 to 64, and 10.3% who were 65 years of age or older. The median age was 37 years. For every 100 females, there were 110.8 males. For every 100 females age 18 and over, there were 106.4 males.
The median income for a household in the town was $43,942, and the median income for a family was $48,529. Males had a median income of $32,014 versus $26,336 for females. The per capita income for the town was $18,415. About 4.5% of families and 7.3% of the population were below the poverty line, including 5.6% of those under age 18 and 6.3% of those age 65 or over.