For geographic and demographic information on specific parts of the town of Marshfield, please see the articles on Green Harbor, Marshfield (CDP), Marshfield Hills, and Ocean Bluff and Brant Rock.
Geography
According to the United States Census Bureau, the town has a total area of 82.2 km² (31.7 mi²). 73.7 km² (28.5 mi²) of it is land and 8.5 km² (3.3 mi²) of it is water. The total area is 10.34% water.
Demographics
As of the census of 2000, there are 24,324 people, 8,905 households, and 6,598 families residing in the town. The population density is 330.1/km² (854.8/mi²). There are 9,954 housing units at an average density of 135.1 persons/km² (349.8 persons/mi²). The racial makeup of the town is 97.69% White, 0.54% African American, 0.11% Native American, 0.37% Asian, 0.02% Pacific Islander, 0.52% from other races, and 0.76% from two or more races. 0.67% of the population are Hispanic or Latino of any race.
There are 8,905 households out of which 37.4% have children under the age of 18 living with them, 60.9% are married couples living together, 10.1% have a woman whose husband does not live with her, and 25.9% are non-families. 20.9% of all households are made up of individuals and 7.2% have someone living alone who is 65 years of age or older. The average household size is 2.73 and the average family size is 3.20.
In the town the population is spread out with 27.4% under the age of 18, 5.7% from 18 to 24, 31.2% from 25 to 44, 26.2% from 45 to 64, and 9.5% who are 65 years of age or older. The median age is 37 years. For every 100 females there are 95.3 males. For every 100 females age 18 and over, there are 91.6 males.
The median income for a household in the town is $66,508, and the median income for a family is $76,541. Males have a median income of $51,600 versus $35,975 for females. The per capita income for the town is $28,768. 5.4% of the population and 3.8% of families are below the poverty line. Out of the total people living in poverty, 6.7% are under the age of 18 and 4.8% are 65 or older.