San Lucas is a census-designated place (CDP) in Monterey County, California, United States. San Lucas is located on the Salinas River 8 miles (13 km) southeast of King City, at an elevation of 410 feet (125 m). The population was 419 at the 2000 census.
According to the United States Census Bureau, the CDP has a total area of 0.4 square miles (1.0 km²), all of it land.
The San Lucas American Viticultural Area is located in the county.
As of the census of 2000, there were 419 people, 90 households, and 81 families residing in the CDP. The population density was 1,092.9 people per square mile (425.7/km²). There were 97 housing units at an average density of 253.0/sq mi (98.6/km²). The racial makeup of the CDP was 38.66% White, 0.24% Black, 1.19% Native American, 1.67% Asian, 55.37% from other races, and 2.86% from two or more races. Hispanic or Latino of any race were 86.16% of the population.
There were 90 households out of which 63.3% had children under the age of 18 living with them, 68.9% were married couples living together, 15.6% had a female householder with no husband present, and 8.9% were non-families. 5.6% of all households were made up of individuals and 2.2% had someone living alone who was 65 years of age or older. The average household size was 4.66 and the average family size was 4.71.
In the CDP the population was spread out with 44.2% under the age of 18, 10.0% from 18 to 24, 26.3% from 25 to 44, 12.4% from 45 to 64, and 7.2% who were 65 years of age or older. The median age was 22 years. For every 100 females there were 118.2 males. For every 100 females age 18 and over, there were 116.7 males.
The median income for a household in the CDP was $31,538, and the median income for a family was $30,536. Males had a median income of $27,000 versus $24,375 for females. The per capita income for the CDP was $7,834. About 23.3% of families and 29.7% of the population were below the poverty line, including 38.2% of those under age 18 and 11.4% of those age 65 or over.