Greer County, Texas

Greer County, a county created by the Texas legislature on February 8, 1860 (and was named for John Alexander Greer, Lieutenant Governor of Texas), was land claimed by both Texas and the United States. The region of Greer County is now in present-day Oklahoma.

Origin of the dispute
The dispute arose from a map submitted with the Adams–Onís Treaty of 1819. The treaty stated that the boundary between the French claims on the north and the Spanish claims on the south was Rio Roxo de Natchitoches (Red River) until it reached the 100th meridian west as noted on John Melish's map published in 1818. The problem was that the 100th meridian on the Melish map was some 90 mi east of the true 100th meridian and the Red River forked about 50 mi east of the 100th meridian. Texas claimed the land south of the North Fork (red on the map) and the United States claimed the land north of the South Fork (blue on the map, later called the Prairie Dog Town Fork Red River).

United States vs. State of Texas
The dispute resulted in a lawsuit, which was heard by the Supreme Court under its original jurisdiction. The Court's opinion, in United States v. State of Texas, issued on March 16, held that the land of some 1.5 e6acre belonged to the United States. Following that ruling, on May 4, 1896, the land was officially assigned by Congress to Oklahoma Territory. The Greer County Homestead Law, passed just afterwards, gave the Texas settlers the 160 acre they were living on and the option to purchase an additional 160 acres for 1 $/acre.

Legacy
When Oklahoma became the 46th U.S. state on November 16, 1907, old "Greer County" was divided into Greer, Jackson, and southwest Beckham counties. Harmon County was created May 22, 1909 by a vote of the people from a portion of Greer County.