There were 6,113 households out of which 20.40% had children under the age of 18 living with them, 47.50% were married couples living together, 8.60% had a female householder with no husband present, and 40.80% were non-families. 35.90% of all households were made up of individuals and 19.30% had someone living alone who was 65 years of age or older. The average household size was 2.13 and the average family size was 2.75.
In the county the population was spread out with 20.10% under the age of 18, 5.40% from 18 to 24, 19.50% from 25 to 44, 27.40% from 45 to 64, and 27.70% who were 65 years of age or older. The median age was 49 years. For every 100 females there were 100.00 males. For every 100 females age 18 and over, there were 97.70 males.
The median income for a household in the county was $24,152, and the median income for a family was $29,787. Males had a median income of $24,570 versus $19,839 for females. The per capita income for the county was $15,023. About 13.80% of families and 20.90% of the population were below the poverty line, including 31.50% of those under age 18 and 14.70% of those age 65 or over.
Spaceport America is located in Sierra County, 45 miles (72 km) north of Las Cruces and 30 miles (48 km) east of Truth or Consequences. Sierra County voters approved the creation of a spaceport tax district in April 2008, freeing up funding for its construction.