Burlington County dates back to 1681, when its court was established. The county was formed on May 17, 1694, "by the union of the first and second Tenths".
This county is part of the Philadelphia Metropolitan Area.
As of the census of 2000, there were 423,394 people, 154,371 households, and 111,610 families residing in the county. The population density was 526 people per square mile (203/km²). There were 161,311 housing units at an average density of 200 per square mile (77/km²). The racial makeup of the county was 78.39% White, 15.13% Black or African American, 0.21% Native American, 2.69% Asian, 0.03% Pacific Islander, 1.48% from other races, and 2.07% from two or more races. 4.16% of the population were Hispanic or Latino of any race. 16.0% were of Irish, 15.6% Italian, 13.3% German, 7.4% English and 5.4% Polish ancestry according to Census 2000.
There were 154,371 households out of which 34.30% had children under the age of 18 living with them, 57.70% were married couples living together, 10.90% had a female householder with no husband present, and 27.70% were non-families. 22.90% of all households were made up of individuals and 8.50% had someone living alone who was 65 years of age or older. The average household size was 2.65 and the average family size was 3.14.
In the county the population was spread out with 25.20% under the age of 18, 7.50% from 18 to 24, 31.50% from 25 to 44, 23.30% from 45 to 64, and 12.60% who were 65 years of age or older. The median age was 37 years. For every 100 females there were 97.90 males. For every 100 females age 18 and over, there were 95.60 males.
The median income for a household in the county was $58,608, and the median income for a family was $67,481 (these figures had risen to $72,466 and $85,117 respectively as of a 2007 estimate). Males had a median income of $46,381 versus $32,228 for females. The per capita income for the county was $26,339. About 3.20% of families and 4.70% of the population were below the poverty line, including 5.50% of those under age 18 and 4.90% of those age 65 or over.