The city of Piedmont is entirely surrounded by the city of Oakland, California.
As of the census of 2000, there are 10,952 people, 3,804 households, and 3,104 families residing in the city. The population density is 2,502.1/km² (6,488.7/mi²). There are 3,859 housing units at an average density of 881.6/km² (2,286.3/mi²). The racial makeup of the city is 78.59% White, 1.24% African American, 0.11% Native American, 16.02% Asian, 0.04% Pacific Islander, 0.63% from other races, and 3.38% from two or more races. 2.97% of the population are Hispanic or Latino of any race.
There are 3,804 households out of which 47.3% have children under the age of 18 living with them, 70.9% are married couples living together, 8.5% have a female householder with no husband present, and 18.4% are non-families. 14.5% of all households are made up of individuals and 7.8% have someone living alone who is 65 years of age or older. The average household size is 2.88 and the average family size is 3.18.
In the city the population is spread out with 30.3% under the age of 18, 3.8% from 18 to 24, 18.5% from 25 to 44, 34.0% from 45 to 64, and 13.5% who are 65 years of age or older. The median age is 44 years. For every 100 females there are 92.7 males. For every 100 females age 18 and over, there are 87.8 males.
The median income for a household in the city is $134,270, and the median income for a family is $149,857. Males have a median income of $100,000 versus $58,553 for females. The per capita income for the city is $70,539. 2.0% of the population and 1.0% of families are below the poverty line. Out of the total people living in poverty, 2.6% are under the age of 18 and 1.6% are 65 or older.