There were 258,439 households out of which 36.52% had children under the age of 18 living with them, 53.21% were married couples living together, 10.27% had a female householder with no husband present, and 33.05% were non-families. 26.12% of all households were made up of individuals and 7.35% had someone living alone who was 65 years of age or older. The average household size was 2.55 and the average family size was 3.11.
In the district the population distribution by age is 26.60% under the age of 18, 10.49% from 18 to 24, 31.65% from 25 to 44, 21.17% from 45 to 64, and 10.09% who were 65 years of age or older. The median age was 33.6 years. For every 100 females there were 95.78 males. For every 100 females age 18 and over, there were 92.54 males.
The median income for a household in the district is $51,118, and the median income for a family was $62,695. Males had a median income of $42,348 versus $30,353 for females. The per capita income for the district was $26,133. About 4.9% of families and 7.8% of the population were below the poverty line, including 8.7% of those under age 18 and 6.0% of those age 65 or over.
Among the population aged 16 years and older, 71.0% was in the civilian labor force and 0.1% were in the armed forces. Of the employed civilian workers, 12.8% were government workers and 5.6% were self-employed. Management, professional, and related occupations employed 41.5% of the work force and sales and office occupations an additional 28.8%. Only 0.2% were employed in farming, fishing, and forestry occupations. The largest employment by industry was: educational, health and social services, 19.8%; professional, scientific, management, administrative, and waste management services, 12.0%; retail trade, 11.8%; and manufacturing, 10.4%. Agriculture, forestry, fishing and hunting, and mining industries only employed 0.4%.