For geographic and demographic information on specific parts of the town of Sandwich, please see the articles on East Sandwich, Forestdale, Pocasset, Popponesset, Popponesset Island, and Sandwich (CDP).
Geography
According to the United States Census Bureau, the town has a total area of 114.9 km² (44.4 mi²). 111.5 km² (43.0 mi²) of it is land and 3.4 km² (1.3 mi²) of it is water. The total area is 2.98% water.
Demographics
As of the census of 2000, there are 20,136 people, 7,335 households, and 5,515 families residing in the town. The population density is 180.6/km² (467.9/mi²). There are 8,748 housing units at an average density of 78.5 persons/km² (203.3 persons/mi²). The racial makeup of the town is 97.75% White, 0.38% African American, 0.31% Native American, 0.54% Asian, 0.01% Pacific Islander, 0.32% from other races, and 0.69% from two or more races. 0.80% of the population are Hispanic or Latino of any race.
There are 7,335 households out of which 38.1% have children under the age of 18 living with them, 65.0% are married couples living together, 8.1% have a woman whose husband does not live with her, and 24.8% are non-families. 20.0% of all households are made up of individuals and 8.9% have someone living alone who is 65 years of age or older. The average household size is 2.72 and the average family size is 3.18.
In the town the population is spread out with 28.4% under the age of 18, 4.9% from 18 to 24, 27.7% from 25 to 44, 25.3% from 45 to 64, and 13.7% who are 65 years of age or older. The median age is 40 years. For every 100 females there are 94.5 males. For every 100 females age 18 and over, there are 89.2 males.
The median income for a household in the town is $61,250, and the median income for a family is $66,553. Males have a median income of $49,195 versus $33,516 for females. The per capita income for the town is $26,895. 3.1% of the population and 2.2% of families are below the poverty line. Out of the total people living in poverty, 3.3% are under the age of 18 and 4.1% are 65 or older.