Shamrock is a city in Wheeler County, Texas, United States. As of the 2000 census, the city had a total population of 2,029. The city is located in the eastern portion of the Texas Panhandle centered along the crossroads of Interstate 40 (formerly U.S. Route 66) and U.S. Route 83. It is 110 miles (180 km) east of Amarillo, 188 miles (303 km) west of Oklahoma City, Oklahoma, and 291 miles (468 km) northwest of Dallas.
Located in south central Wheeler County, Shamrock was the largest town in the county in the late 19th century. It was given its name by an Irish immigrant, George Nickel, who wanted to open a post office there in 1890. Though his post office was never opened, Mary Jones ran her own post office, also with the name Shamrock, for a short time. In 1902 the Chicago, Rock Island and Gulf Railway set up a station in the town, calling it "Wheeler" like the county, but changing it to the original name of Shamrock in 1903, which prompted the reopening of the Shamrock post office. By 1907, the town was competing with the towns of Story and Benonine as trade centers.
The town continued its growth as other businesses moved into the city, including the county newspaper, which moved from Story and renamed itself from the Wheeler County Texan to the Shamrock Texan, several banks, and Shamrock Cotton Oil Mill. In 1911, E. L. Woodley became the mayor of the newly incorporated city. In 1926, the discovery of oil and the operation of natural gas wells by Shamrock Gas Company helped spur the city's continuing growth. A decline in the oil industry caused the population to drop in the 1940s, but it rebounded in the next decade with the improvement of Route 66. By the 1980s, the town was home to an established modern school system, a chemical plant, oil and gas processing plants, and a hospital.