The Nueces Strip or Wild Horse Desert is the area of south Texas between the Nueces River and the Rio Grande. The Republic of Texas claimed the Rio Grande as its southern border; Mexico claimed the Nueces River (150 mi or 240 km north of the Rio Grande). The area between the two rivers became known as the Nueces Strip. Both countries invaded it, but neither controlled it nor settled it.
U.S. President James K. Polk ordered General Zachary Taylor and his forces south to the Rio Grande, entering the Nueces Strip. The U.S. claimed the land citing the 1836 Treaties of Velasco. Mexico rejected the treaties and refused to negotiate; it claimed all of Texas. Taylor ignored Mexican demands to withdraw to the Nueces. He constructed a makeshift fort (later known as Fort Brown/Fort Texas) on the banks of the Rio Grande opposite the city of Matamoros, Tamaulipas.
Mexican forces under General Mariano Arista prepared for war. On April 25, 1846, a 2,000-strong Mexican cavalry detachment attacked a 70-man U.S. patrol that had been sent into the contested territory north of the Rio Grande and south of the Nueces River. In the Thornton Affair, the Mexican cavalry routed the patrol, killing 16 American soldiers.
- Durham, George (1982). Taming the Nueces Strip: The Story of McNelly's Rangers. University of Texas Press.
- Richardson, Chad, and Michael J. Pisani, eds. The Informal and Underground Economy of the South Texas Border (University of Texas Press; 2012) 335 pages; explores the risks and benefits of an "undocumented economy" in the region known as the Nueces Strip.
- Teague, Wells (2000). Calling Texas Home: A Lively Look at What It Means to Be a Texan. Council Oak Books. pp. 23–24. ISBN 9781885171382.
- Richardson and Pisani, 2012
- Durham, 1982
- David Montejano (1987). Anglos and Mexicans in the Making of Texas, 1836-1986. University of Texas Press. p. 30.
- Justin Harvey Smith (1919). The war with Mexico vol. 1. Macmillan. p. 464.
- K. Jack Bauer (1993). Zachary Taylor: Soldier, Planter, Statesman of the Old Southwest. Louisiana State University Press. p. 149.