For geographic and demographic information on specific parts of the town of Dennis, please see the articles on Dennis (CDP), Dennis Port, East Dennis, South Dennis, and West Dennis.
Geography
According to the United States Census Bureau, the town has a total area of 57.6 km² (22.2 mi²). 53.4 km² (20.6 mi²) of it is land and 4.2 km² (1.6 mi²) of it is water. The total area is 7.38% water.
Demographics
As of the census of 2000, there are 15,973 people, 7,504 households, and 4,577 families residing in the town. The population density is 299.4/km² (775.6/mi²). There are 14,105 housing units at an average density of 264.4 persons/km² (684.9 persons/mi²). The racial makeup of the town is 94.99% White, 1.93% African American, 0.37% Native American, 0.37% Asian, 0.00% Pacific Islander, 0.88% from other races, and 1.46% from two or more races. 1.65% of the population are Hispanic or Latino of any race.
There are 7,504 households out of which 18.8% have children under the age of 18 living with them, 49.0% are married couples living together, 9.2% have a woman whose husband does not live with her, and 39.0% are non-families. 33.3% of all households are made up of individuals and 17.7% have someone living alone who is 65 years of age or older. The average household size is 2.11 and the average family size is 2.65.
In the town the population is spread out with 16.9% under the age of 18, 4.6% from 18 to 24, 22.2% from 25 to 44, 27.8% from 45 to 64, and 28.4% who are 65 years of age or older. The median age is 49 years. For every 100 females there are 85.6 males. For every 100 females age 18 and over, there are 82.7 males.
The median income for a household in the town is $41,598, and the median income for a family is $50,478. Males have a median income of $40,528 versus $29,153 for females. The per capita income for the town is $25,428. 7.0% of the population and 5.4% of families are below the poverty line. Out of the total people living in poverty, 10.4% are under the age of 18 and 4.8% are 65 or older.