Castroville is a somewhat small town located in the state of California. With a population of 7,515 people and two associated neighborhoods, Castroville is the 456th largest community in California.

Housing costs in Castroville are among some of the highest in the nation, although real estate prices here don't compare to real estate prices in the most expensive communities in California.

The population of Castroville has one of the lowest overall levels of education in the country: only 5.10% of people over 25 hold a college degree. The national average for all municipalities is 21.84%.

The per capita income in Castroville in 2018 was $18,689, which is low income relative to California and the nation. This equates to an annual income of $74,756 for a family of four. However, Castroville contains both very wealthy and poor people as well.

Castroville is an extremely ethnically-diverse town. The people who call Castroville home describe themselves as belonging to a variety of racial and ethnic groups. People of Hispanic or Latino origin are the most prevalent group in Castroville, accounting for 86.06% of the town’s residents (people of Hispanic or Latino origin can be of any race). The greatest number of Castroville residents report their race to be White, followed by Asian. Important ancestries of people in Castroville include English, Irish, Italian, Swiss, and Nigerian.

Foreign born people are also an important part of Castroville's cultural character, accounting for 37.31% of the town’s population.

The most common language spoken in Castroville is Spanish. Other important languages spoken here include English and Korean.