Texas panhandle

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 Panhandle 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.

Its land area is 25,823.89 sq mi (66,883.58 km), or nearly 10% of the state's total. The Texas Panhandle is slightly larger in size than the US state of West Virginia. An additional 62.75 sq mi (162.53 km) is covered by water. Its population as of the 2010 census was 427,927 residents, or 1.7% of the state's total population. As of the 2010 census, the population density for the region was 16.6 per square mile (6.4/km). However, more than 72% of the Panhandle's residents live in the Amarillo Metropolitan Area, which is the largest and fastest-growing urban area in the region. Despite being geographically the northernmost part of Texas, the Panhandle is distinct from the region commonly called "North Texas", which is to the south and east.

The western edge of the panhandle, defined as the 103rd meridian west also served as the western boundary of the Oklahoma panhandle. The 103rd meridian became known as the Cimarron Meridian, and along with the Cimarron Territory was named for the Cimarron River. Surveyors first marked Texas's portion of the meridian in 1859. The boundary marked by this survey was inaccurately placed between 2 and 4 miles too far west. The northwest corner of Texas is at roughly 103.04° west, 12,234 feet to west of the Cimmaron Meridian. The southernmost point on Texas's border intended to be on the Cimmaron Meridian is at 103.06° west, 19,962 feet too far west. These surveying errors give Texas close to 1,000 square miles of land that was intended to be part of New Mexico under the Compromise of 1850. Although Oklahoma shared the Cimmaron Meridian as its western border, its surveyors were more accurate, meaning that Texas's panhandle extends farther west than Oklahoma's.