As of the census of 2000, there were 33,049 people, 8,800 households, and 7,048 families residing in the city. The population density was 2,502.0/km² (6,482.4/mi²). There were 9,066 housing units at an average density of 686.4/km² (1,778.3/mi²). The racial makeup of the city was 44.8% White, 6.4% African American, 1.0% Native American, 8.1% Asian, 0.3% Pacific Islander, 34.6% from other races, and 4.8% from two or more races. Hispanic or Latino of any race were 82.0% of the population.

There were 8,800 households out of which 47.5% had children under the age of 18 living with them, 46.3% were married couples living together, 26.3% had a female householder with no husband present, and 19.9% were non-families. 15.0% of all households were made up of individuals and 6.3% had someone living alone who was 65 years of age or older. The average household size was 3.69 and the average family size was 4.04.

In the city the population was spread out with 33.1% under the age of 18, 10.7% from 18 to 24, 30.4% from 25 to 44, 17.4% from 45 to 64, and 8.3% who were 65 years of age or older. The median age was 29 years. For every 100 females there were 99.6 males. For every 100 females age 18 and over, there were 96.2 males.

The median income for a household in the city was $27,797, and the median income for a family was $32,815. Males had a median income of $25,902 versus $23,014 for females. The per capita income for the city was $13,556. About 29.2% of families and 31.4% of the population were below the poverty line, including 28.6% of those under age 18 and 19.1% of those age 65 or over.

Due to the high poverty rate but low population, Montclair has a reputation for trouble and extreme drug use. The city is known for having 'cooks' and the murder rate is high compared to the national average even though the actual number of murders is low compared to larger local cities such as LA or San Bernardino.

History

The earliest known inhabitants of the area were from the Serrano tribe of Native Americans. The Serrano established their village along a creek named Arroyo de los Alisos, now named San Antonio Creek, which flowed along a route that is now Mills Avenue, the western border of the city.

In 1897, a "Township of Marquette" was founded within the borders of the modern city of Montclair. In 1900, a 1000 acre (4 km²) tract of land was surveyed and named "Monte Vista". A small settlement to the south of Monte Vista was established in 1907 and named "Narod". Throughout the first half of the 20th century, the settlement was largely devoted to citrus orchards. The Monte Vista tract experienced growth in residential development after the Second World War, and the tract was incorporated as the city of Monte Vista on April 25, 1956. Due to conflict with the Post Office, which refused to open an office in Monte Vista due to a name conflict with a community in Northern California, the city was renamed Montclair on April 8, 1958.