Geography According to the U.S. Census Bureau, the county has a total area of 2,146 km² (829 mi²). 1,297 km² (501 mi²) of it is land and 849 km² (328 mi²) of it is water. The total area is 39.57% water.
Demographics As of the census of 2000, there are 723,419 people, 275,419 households, and 185,081 families residing in the county. The population density is 558/km² (1,445/mi²). There are 287,144 housing units at an average density of 221/km² (574/mi²). The racial makeup of the county is 86.44% White, 2.60% African American, 0.23% Native American, 2.34% Asian, 0.04% Pacific Islander, 6.20% from other races, and 2.15% from two or more races. 11.04% of the population are Hispanic or Latino of any race.
There are 275,419 households out of which 32.80% have children under the age of 18 living with them, 51.10% are married couples living together, 12.40% have a female householder with no husband present, and 32.80% are non-families. 27.10% of all households are made up of individuals and 10.90% have someone living alone who is 65 years of age or older. The average household size is 2.57 and the average family size is 3.15.
In the county the population is spread out with 25.20% under the age of 18, 7.50% from 18 to 24, 30.30% from 25 to 44, 23.10% from 45 to 64, and 13.90% who are 65 years of age or older. The median age is 38 years. For every 100 females there are 91.90 males. For every 100 females age 18 and over, there are 87.80 males.
The median income for a household in the county is $51,576, and the median income for a family is $63,746. Males have a median income of $44,569 versus $32,369 for females. The per capita income for the county is $26,358. 8.90% of the population and 6.60% of families are below the poverty line. Out of the total people living in poverty, 11.90% are under the age of 18 and 8.90% are 65 or older.