The county, which was formerly much larger in area, lost almost 81 percent of its territory on 19 June 1981, upon the creation of Cibola County, which occupies the westernmost portion of Valencia County's former area.
Geography
According to the U.S. Census Bureau, the county has a total area of, of which is land and is water. It is the second-smallest county in New Mexico by area.
As of the 2000 census, there were 66,152 people, 22,681 households, and 17,350 families living in the county. The population density was 62 people per square mile. There were 24,643 housing units at an average density of 23 per square mile. The racial makeup of the county was 66.51% White, 1.27% Black or African American, 3.30% Native American, 0.36% Asian, 0.09% Pacific Islander, 23.93% from other races, and 4.55% from two or more races. 54.98% of the population were Hispanic or Latino of any race. There were 22,681 households out of which 39.60% had children under the age of 18 living with them, 57.20% were married couplesliving together, 13.10% had a female householder with no husband present, and 23.50% were non-families. 18.80% of all households were made up of individuals and 6.40% had someone living alone who was 65 years of age or older. The average household size was 2.86 and the average family size was 3.25. In the county, the population was spread out with 30.10% under the age of 18, 8.40% from 18 to 24, 29.60% from 25 to 44, 21.70% from 45 to 64, and 10.20% who were 65 years of age or older. The median agewas 34 years. For every 100 females there were 100.70 males. For every 100 females age 18 and over, there were 99.10 males. The median income for a household in the county was $34,099, and the median income for a family was $37,157. Males had a median income of $30,339 versus $23,132 for females. The per capita income for the county was $14,747. About 13.50% of families and 16.80% of the population were below the poverty line, including 22.30% of those under age 18 and 10.80% of those age 65 or over.
2010 census
As of the 2010 census, there were 76,569 people, 27,500 households, and 19,967 families living in the county. The population density was. There were 30,085 housing units at an average density of. The racial makeup of the county was 73.2% white, 3.8% American Indian, 1.4% black or African American, 0.5% Asian, 0.1% Pacific islander, 17.0% from other races, and 4.0% from two or more races. Those of Hispanic or Latino origin made up 58.3% of the population. In terms of ancestry, 10.9% were German, 6.7% were English, 6.1% were Irish, and 4.2% were American. Of the 27,500 households, 37.1% had children under the age of 18 living with them, 51.8% were married couples living together, 13.9% had a female householder with no husband present, 27.4% were non-families, and 22.1% of all households were made up of individuals. The average household size was 2.73 and the average family size was 3.18. The median age was 37.7 years. The median income for a household in the county was $42,044 and the median income for a family was $48,767. Males had a median income of $41,511 versus $32,584 for females. The per capita income for the county was $19,955. About 15.7% of families and 19.4% of the population were below the poverty line, including 29.7% of those under age 18 and 12.5% of those age 65 or over.
Valencia County has the longest active streak of voting for the winner of U.S. presidential elections, having voted for the winner in every presidential election from 1952 onward.
