Los Fresnos (Spanish for "The Ash Trees") is a city in Cameron County, Texas, United States. The population was 6,542 at the 2010 census, up from 4,512 at the 2000 census. It is part of the Brownsville–Harlingen–Raymondville and the Matamoros-Brownsville metropolitan areas.
Los Fresnos is located slightly south of the geographic center of Cameron County at 26°4′24″N 97°28′41″W (26.073216, -97.478164). It is 12 miles (19 km) north of the center of Brownsville and 18 miles (29 km) southeast of Harlingen.
According to the United States Census Bureau, Los Fresnos has a total area of 3.1 square miles (7.9 km2), of which 2.9 square miles (7.6 km2) is land and 0.1 square miles (0.3 km2), or 3.98%, is water.
As of the census of 2000, there were 4,512 people, 1,296 households, and 1,092 families residing in the city. The population density was 1,868.9 people per square mile (722.9/km²). There were 1,480 housing units at an average density of 613.0 per square mile (237.1/km²). The racial makeup of the city was 81.96% White, 0.42% African American, 0.13% Native American, 0.02% Asian, 0.09% Pacific Islander, 14.38% from other races, and 2.99% from two or more races. Hispanic or Latino of any race were 84.62% of the population.
There were 1,296 households out of which 53.5% had children under the age of 18 living with them, 63.7% were married couples living together, 17.7% had a female householder with no husband present, and 15.7% were non-families. 14.2% of all households were made up of individuals and 7.7% had someone living alone who was 65 years of age or older. The average household size was 3.48 and the average family size was 3.86.
In the city, the population was spread out with 36.4% under the age of 18, 9.2% from 18 to 24, 29.2% from 25 to 44, 17.1% from 45 to 64, and 8.1% who were 65 years of age or older. The median age was 28 years. For every 100 females, there were 93.8 males. For every 100 females age 18 and over, there were 84.6 males.
The median income for a household in the city was $25,793, and the median income for a family was $27,670. Males had a median income of $20,459 versus $17,904 for females. The per capital income for the city was $9,507. About 28.5% of families and 34.2% of the population were below the poverty line, including 43.8% of those under age 18 and 22.4% of those age 65 or over.