How did the Treaty of Guadalupe Hidalgo establish the Rio Grande as an international boundary?

The Treaty of Guadalupe Hidalgo, signed on February 2, 1848, formally ended the Mexican-American War and resolved a long-standing border dispute between the United States and Mexico.123

Prior to the treaty, the two nations held conflicting claims regarding the boundary of Texas. Mexico maintained that the border was at the Nueces River, while the United States insisted it was at the Rio Grande. By establishing the Rio Grande as the official international boundary, the treaty codified the American position and concluded the territorial disagreement.431

To ensure the boundary was clearly defined, the treaty mandated that a joint survey team, consisting of representatives from both the United States and Mexico, would be responsible for demarcating the border. In addition to the Rio Grande, the treaty also utilized the Gila River as part of the new frontier between the two countries. This agreement facilitated the Mexican Cession, resulting in the transfer of vast territories to the United States.31