This county is a part of the Washington-Baltimore Metropolitan Area.

There are 59,900 households out of which 43.10% have children under the age of 18 living with them, 64.30% are married couples living together, 7.80% have a female householder with no husband present, and 24.80% are non-families. 18.40% of all households are made up of individuals and 3.70% have someone living alone who is 65 years of age or older. The average household size is 2.82 and the average family size is 3.24.

In the county, the population is spread out with 29.80% under the age of 18, 5.70% from 18 to 24, 38.90% from 25 to 44, 20.00% from 45 to 64, and 5.60% who are 65 years of age or older. The median age is 34 years. For every 100 females there are 97.80 males. For every 100 females age 18 and over, there are 95.50 males.

The median income for a household in the county is $80,648, and the median income for a family is $88,387. Males have a median income of $58,869 versus $40,107 for females. The per capita income for the county is $33,530. 2.80% of the population and 1.70% of families are below the poverty line. Out of the total people living in poverty, 2.60% are under the age of 18 and 4.70% are 65 or older.

- Dulles
- Hamilton
- Hillsboro
- Leesburg
- Lovettsville
- Mechanicsville
- Middleburg
- Potomac Falls
- Purcellville
- Round Hill
- South Riding