West Caldwell was incorporated as a borough by an Act of the New Jersey Legislature on February 24, 1904, from portions of Caldwell Township (now known as Fairfield Township). In 1981, West Caldwell became a township to take advantage of federal revenue sharing policies.
Though today the Caldwell area is considered to be a suburb of both Newark and New York, the area originally developed as its own individual, self-contained town and economy rather than as urban sprawl from a larger city. When it was formed, a few miles of woods separated downtown Caldwell from Newark or any of its developing suburbs.
New Jersey Monthly magazine ranked West Caldwell as its 30th best place to live in its 2008 rankings of the "Best Places To Live" in New Jersey.
As of the census of 2000, there were 11,233 people, 3,990 households, and 3,112 families residing in the township. The population density was 2,224.4 people per square mile (858.8/km²). There were 4,044 housing units at an average density of 800.8/sq mi (309.2/km²). The racial makeup of the township was 93.84% White, 0.89% African American, 0.04% Native American, 3.85% Asian, 0.04% Pacific Islander, 0.61% from other races, and 0.75% from two or more races. Hispanic or Latino of any race were 2.80% of the population.
There were 3,990 households out of which 35.3% had children under the age of 18 living with them, 68.1% were married couples living together, 7.4% had a female householder with no husband present, and 22.0% were non-families. 19.2% of all households were made up of individuals and 11.2% had someone living alone who was 65 years of age or older. The average household size was 2.75 and the average family size was 3.17.
In the township the population was spread out with 24.7% under the age of 18, 4.6% from 18 to 24, 27.6% from 25 to 44, 24.0% from 45 to 64, and 19.1% who were 65 years of age or older. The median age was 41 years. For every 100 females there were 90.3 males. For every 100 females age 18 and over, there were 86.2 males.
The median income for a household in the township was $83,396, and the median income for a family was $94,379. Males had a median income of $67,108 versus $45,365 for females. The per capita income for the township was $38,345. About 1.2% of families and 2.1% of the population were below the poverty line, including 2.5% of those under age 18 and 2.4% of those age 65 or over.