Randolph B. Marcy, U.S. Fifth Infantry Captain, and George B. McClellan led a company into the Texas panhandle in 1852 to determine the locations of the headwaters of the Red River. That summer the team discovered two main branches of the Upper Red River that intersect the 100th Meridan. The North Branch is southeast of Pampa. Earlier treaties used the Red River as a boundary, but it was unclear which fork was meant when first defined. In 1896, the South Branch was determined to be the main stream and the boundary between Texas and Oklahoma. (1984, 1996)