Deaf Smith County is a county located in the U.S. state of Texas. Mainly made up of farm land, its county seat is Hereford, known as the "Beef Capital of the World". As of the 2010 census, the population was 19,372. .
The Hereford Micropolitan Statistical Area includes all of Deaf Smith County.
In 1876 the state legislature identified and named the county, but it was not organized until 1890, with the town of LaPlata as the original county seat. The county was named for Erastus "Deaf" Smith (1787–1837), a partially deaf scout and soldier who served in the Texas Revolution. The pronunciation of "Deaf", like that of Smith himself, is "Deef". He was the first to reach the Alamo after its fall. Most people in Deaf Smith County, however, pronounce it "Deaf".
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.