Armstrong County is a county located in the U.S. state of Texas. As of the 2010 census, the population was 1,901. Its county seat is Claude. The county was formed in 1876 and later organized in 1890. It was named for one of several Texas pioneer families named Armstrong.
According to the U.S. Census Bureau, the county has a total area of 914 square miles (2,370 km), of which 909 square miles (2,350 km) are land and 4.7 square miles (12 km) (0.5%) are covered by water.
As of the census of 2000, 2,148 people, 802 households, and 612 families resided in the county. The population density was 2 people per square mile (1/km²). The 920 housing units averaged 1 per square mile (0/km²). The racial makeup of the county was 95.44% White, 0.28% Black or African American, 0.65% Native American, 2.79% from other races, and 0.84% from two or more races. About 5.40% of the population was Hispanic or Latino of any race.
Of the 802 households, 33.90% had children under the age of 18 living with them, 67.20% were married couples living together, 6.10% had a female householder with no husband present, and 23.60% were non-families. About 21.40% of all households were made up of individuals, and 12.00% had someone living alone who was 65 years of age or older. The average household size was 2.58 and the average family size was 2.99.
In the county, the population was distributed as 26.00% under the age of 18, 6.10% from 18 to 24, 24.80% from 25 to 44, 23.80% from 45 to 64, and 19.20% who were 65 years of age or older. The median age was 41 years. For every 100 females, there were 93.20 males. For every 100 females age 18 and over, there were 90.30 males.
The median income for a household in the county was $38,194, and for a family was $43,894. Males had a median income of $30,114 versus $21,786 for females. The per capita income for the county was $17,151. About 7.90% of families and 10.60% of the population were below the poverty line, including 15.80% of those under age 18 and 11.60% of those age 65 or over.