According to the United States Census Bureau, the town has a total area of 27.0 km² (10.4 mi²). 10.2 km² (3.9 mi²) of it is land and 16.9 km² (6.5 mi²) of it is water. The total area is 62.45% water.
As of the census of 2000, there are 10,468 people, 5,789 households, and 3,021 families residing in the town. The population density is 1,031.1/km² (2,669.2/mi²). There are 9,948 housing units at an average density of 979.8/km² (2,536.6/mi²). The racial makeup of the town is 96.00% White, 2.57% African American, 0.04% Native American, 0.53% Asian, 0.02% Pacific Islander, 0.21% from other races, and 0.63% from two or more races. 2.56% of the population are Hispanic or Latino of any race.
There are 5,789 households out of which 7.7% have children under the age of 18 living with them, 48.1% are married couples living together, 3.3% have a female householder with no husband present, and 47.8% are non-families. 42.6% of all households are made up of individuals and 27.6% have someone living alone who is 65 years of age or older. The average household size is 1.81 and the average family size is 2.38.
In the town the population is spread out with 9.4% under the age of 18, 1.5% from 18 to 24, 11.5% from 25 to 44, 25.0% from 45 to 64, and 52.6% who are 65 years of age or older. The median age is 67 years. For every 100 females there are 79.3 males. For every 100 females age 18 and over, there are 77.0 males.
The median income for a household in the town is $94,562, and the median income for a family is $137,867. Males have a median income of $71,685 versus $42,875 for females. The per capita income for the town is $109,219. 5.3% of the population and 2.4% of families are below the poverty line. Out of the total people living in poverty, 4.6% are under the age of 18 and 2.9% are 65 or older.