Plymouth was the landing site of the Mayflower and the location of the original settlement of the Plymouth Colony, established by the Pilgrims in 1620. Today it is a tourist destination for that reason, and is home to Plymouth Rock and the living-history village Plimoth Plantation.
According to the United States Census Bureau, the town has a total area of 347.0 km² (134.0 mi²). 249.8 km² (96.5 mi²) of it is land and 97.2 km² (37.5 mi²) of it is water. The total area is 28.00% water. Plymouth has the largest land area of any city or town in Massachusetts.
As of the census of 2000, there are 51,701 people, 18,423 households, and 13,264 families residing in the town. The population density is 206.9/km² (536.0/mi²). There are 21,250 housing units at an average density of 85.1 persons/km² (220.3 persons/mi²). The racial makeup of the town is 94.82% White, 1.91% African American, 0.25% Native American, 0.57% Asian, 0.04% Pacific Islander, 0.93% from other races, and 1.48% from two or more races. 1.68% of the population are Hispanic or Latino of any race.
There are 18,423 households out of which 36.0% have children under the age of 18 living with them, 58.4% are married couples living together, 10.4% have a woman whose husband does not live with her, and 28.0% are non-families. 21.7% of all households are made up of individuals and 8.5% have someone living alone who is 65 years of age or older. The average household size is 2.67 and the average family size is 3.16.
In the town the population is spread out with 25.8% under the age of 18, 7.1% from 18 to 24, 32.0% from 25 to 44, 23.9% from 45 to 64, and 11.2% who are 65 years of age or older. The median age is 36 years. For every 100 females there are 98.8 males. For every 100 females age 18 and over, there are 96.4 males.
The median income for a household in the town is $54,677, and the median income for a family is $63,266. Males have a median income of $44,983 versus $31,565 for females. The per capita income for the town is $23,732. 5.4% of the population and 4.4% of families are below the poverty line. Out of the total people living in poverty, 7.1% are under the age of 18 and 6.9% are 65 or older.