Parmer County is a county located in the southwestern Texas Panhandle on the High Plains of the Llano Estacado in the U.S. state of Texas. As of the 2020 Census, the population was 9,869. The county seat is Farwell. The county was created in 1876 and later organized in 1907. It is named in honor of Martin Parmer, a signer of the Texas Declaration of Independence and early judge. Parmer County was one of 10 prohibition, or entirely dry, counties in the state of Texas, but is now a wet county.

The Texas panhandle is a region of the U.S. state of Texas consisting of the northernmost 26 counties in the state. The panhandle is a square-shaped area bordered by New Mexico to the west and Oklahoma to the north and east. It is adjacent to the Oklahoma Panhandle, land which Texas previously claimed. The 1820 Missouri Compromise declared no slavery would be allowed in states admitted from the Louisiana Purchase above 36°30′ north latitude. Texas was annexed in 1845 from still more westerly land. The Compromise of 1850 removed territory north of this line from Texas, and set the border between the Texas Pandhandle and the New Mexico Territory at the 103rd meridian west. The eastern border at the 100th meridian west was inherited from the Adams–Onís Treaty of 1819, which defined the border between the United States and New Spain. The Handbook of Texas defines the southern border of Swisher County as the southern boundary of the Texas Panhandle region.