Los Alvarez is a census-designated place (CDP) in Starr County, Texas, United States. The population was 303 at the 2010 census down from 1,434 at the 2000 census.
Los Alvarez is located at 26°23′09″N 98°53′56″W / 26.38583°N 98.89889°W / 26.38583; -98.89889 (26.385936, -98.899036).
Prior to the 2010 census, parts of the CDP were taken to form new CDPs and additional area was also lost reducing the total area of 0.1 square miles (0.3 km²), all land.
As of the census of 2000, there were 1,434 people, 379 households, and 344 families residing in the CDP. The population density was 425.0 people per square mile (164.3/km²). There were 453 housing units at an average density of 134.3/sq mi (51.9/km²). The racial makeup of the CDP was 66.60% White, 0.07% African American, 32.57% from other races, and 0.77% from two or more races. Hispanic or Latino of any race were 99.44% of the population.
There were 379 households out of which 61.7% had children under the age of 18 living with them, 66.2% were married couples living together, 19.8% had a female householder with no husband present, and 9.0% were non-families. 8.7% of all households were made up of individuals and 4.2% had someone living alone who was 65 years of age or older. The average household size was 3.78 and the average family size was 4.01.
In the CDP, the population was spread out with 38.6% under the age of 18, 11.9% from 18 to 24, 27.5% from 25 to 44, 15.3% from 45 to 64, and 6.7% who were 65 years of age or older. The median age was 24 years. For every 100 females, there were 87.2 males. For every 100 females age 18 and over, there were 84.9 males.
The median income for a household in the CDP was $20,427, and the median income for a family was $21,738. Males had a median income of $20,313 versus $12,679 for females. The per capita income for the CDP was $8,969. About 34.4% of families and 38.0% of the population were below the poverty line, including 47.4% of those under age 18 and 67.4% of those age 65 or over.