Alstead (/ˈælstɛd/) is a town in Cheshire County, New Hampshire, United States. The population was 1,937 at the 2010 census. Alstead is home to Feuer State Forest.
According to the United States Census Bureau, the town has a total area of 39.3 square miles (102 km), of which 38.8 square miles (100 km) is land and 0.6 square miles (1.6 km) is water, comprising 1.45% of the town. Alstead is drained by the Cold River. Lake Warren is in the east. The highest point in Alstead is Smith Hill, at 1,795 feet (547 m) above sea level). Alstead lies fully within the Connecticut River watershed.
The town is served by state routes 123, 123A and 12A.
As of the census of 2000, there were 1,944 people, 771 households, and 534 families residing in the town. The population density was 50.0 people per square mile (19.3/km²). There were 941 housing units at an average density of 24.2 per square mile (9.3/km²). The racial makeup of the town was 98.20% White, 0.21% African American, 0.62% Native American, 0.51% Asian, and 0.46% from two or more races. Hispanic or Latino of any race were 0.51% of the population.
There were 771 households out of which 33.6% had children under the age of 18 living with them, 56.7% were married couples living together, 8.9% had a female householder with no husband present, and 30.7% were non-families. 24.5% of all households were made up of individuals and 8.0% had someone living alone who was 65 years of age or older. The average household size was 2.51 and the average family size was 2.99.
In the town, the population was spread out with 26.0% under the age of 18, 6.1% from 18 to 24, 28.5% from 25 to 44, 26.7% from 45 to 64, and 12.7% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 104.4 males. For every 100 females age 18 and over, there were 98.2 males.
The median income for a household in the town was $43,191, and the median income for a family was $47,311. Males had a median income of $35,481 versus $23,785 for females. The per capita income for the town was $20,444. About 3.5% of families and 7.9% of the population were below the poverty line, including 10.9% of those under age 18 and 4.7% of those age 65 or over.