Caldwell is the home of the College of Idaho. It is considered part of the Boise metropolitan area.
As of the census of 2000, there were 25,967 people, 8,963 households, and 6,354 families residing in the city. The population density was 2,289.3/sq mi. There were 9,603 housing units at an average density of 846.6/sq mi. The racial makeup of the city was 75.07% White 28.14% Hispanic or Latino 0.47% African American 0.94% Native American 0.83% Asian 0.10% Pacific Islander 2.91% two or more races
There were 8,963 households, out of which 39.5% had children under the age of 18, 51.7% were married couples, 13.9% had a female householder with no husband present, and 29.1% were non-families. In addition, 23.3% of all households were made up of a single individual and 10.2% had someone living alone who was 65 years of age or older. The average household size was 2.79, and the average family size was 3.30.
In the city the population was spread out with 30.9% under the age of 18, 13.1% from 18 to 24, 27.3% from 25 to 44, 17.6% from 45 to 64, and 11% who were 65 years of age or older. The median age was 29 years. For every 100 females there were 95.6 males. For every 100 females age 18 and over, there were 92.6 males.
The median income for a household in the city was $30,848, and the median income for a family was $35,158. Males had a median income of $27,017 versus $21,096 for females. The per capita income for the city was $13,657. About 12.6% of families and 16.0% of the population were below the poverty line, including 20.8% of those under age 18 and 15.5% of those age 65 or over.