USA HISTORY

Detailed explanation-1: -Mexico also relinquished all claims to Texas, and recognized the Rio Grande as the southern boundary with the United States.

Detailed explanation-2: -The Treaty of Guadalupe Hidalgo, that brought an official end to the Mexican-American War (1846-1848), was signed on February 2, 1848, at Guadalupe Hidalgo, a city north of the capital where the Mexican government had fled with the advance of U.S. forces.

Detailed explanation-3: -Furthermore, the boundary was in dispute. Mexico claimed that the southern boundary of Texas was the Nueces River, the Texan boundary while under Mexican rule. Americans, as well as the incoming President, claimed that the boundary of Texas was the Rio Grande River.