In 1876, the state legislature defined and named the county, but it was not organized until 1890, with the town of La Plata as the original county seat. The county was named for Erastus "Deaf" Smith, a partially deaf scout and soldier who served in the Texas Revolution and was the first to reach the Alamo after its fall. The pronunciation of "Deaf", like that of Smith himself, is ; however, most residents pronounce it . This county was also selected as an alternate site for a possible nuclear waste disposal repository, but was later dropped. Jesse Frank Ford, founder of Arrowhead Mills, led the opposition to the Deaf Smith site on grounds of contamination of the Ogallala Aquifer, the source of much of the water supply for West Texas.
Geography
According to the U.S. Census Bureau, the county has a total area of, of which is land and is covered by water.
As of the census of 2000, 18,561 people, 6,180 households, and 4,832 families resided in the county. The population density was 12 people per square mile. The 6,914 housing units averaged 5 per square mile. The racial makeup of the county was 72.28% White, 1.51% Black or African American, 0.80% Native American, 0.25% Asian, 0.13% Pacific Islander, 22.92% from other races, and 2.11% from two or more races. About 57.40% of the population was Hispanic or Latino of any race. Of the 6,180 households, 41.00% had children under the age of 18 living with them, 61.00% were married couplesliving together, 12.60% had a female householder with no husband present, and 21.80% were not families. Around 19.70% of all households was made up of individuals and 10.00% had someone living alone who was 65 years of age or older. The average household size was 2.96 and the average family size was 3.41. In the county, the population was distributed as 33.30% under the age of 18, 9.60% from 18 to 24, 25.50% from 25 to 44, 19.40% from 45 to 64, and 12.10% who were 65 years of age or older. The median age was 31 years. For every 100 females, there were 95.50 males. For every 100 females age 18 and over, there were 91.90 males. The median income for a household was $29,601, and for a family was $32,391. Males had a median income of $26,090 versus $19,113 for females. The per capita income for the county was $13,119. About 19.30% of families and 20.60% of the population were below the poverty line, including 26.30% of those under age 18 and 15.70% of those age 65 or over.
