Blaine County is a county located in the U.S. state of Oklahoma. As of the 2020 census, the population was 8,735. Its county seat is Watonga. Part of the Cheyenne-Arapaho land opening in 1892, the county had gained rail lines by the early 1900s and highways by the 1930s. The county was named for James G. Blaine, an American politician who was the Republican presidential candidate in 1884 and Secretary of State under President Benjamin Harrison.

U.S. Route 270 (US 270) is a spur of US 70. It travels for 643 miles (1,035 km) from Liberal, Kansas at US 54 and US 83 to White Hall, Arkansas at Interstate 530 (I-530) and US 65. It travels through the states of Arkansas, Oklahoma, and Kansas. It travels through the cities of Oklahoma City, Oklahoma, Hot Springs, Arkansas, and McAlester, Oklahoma.