Nation did the US fight over a dispute of the location of the Texas border?

The United States fought Mexico over the dispute of the location of the Texas border, which ultimately led to the Mexican-American War from 1846 to 1848. The conflict arose after Texas gained independence from Mexico and was annexed by the U.S., with differing claims over the Rio Grande as the southern border. The war concluded with the Treaty of Guadalupe Hidalgo, which solidified U.S. territorial gains in the Southwest.