USA HISTORY

Detailed explanation-1: -Texas used the Adams-Onís as a boundary line to the U.S., but decided to set the Rio Grande (called the Río Bravo del Norte in Mexico) as its boundary line to Mexico.

Detailed explanation-2: -After the Mexican-American War-during Texas’ first round of being a U.S. state-the 1848 Treaty of Guadalupe-Hidalgo established the Rio Grande as the border between the United States and Mexico.

Detailed explanation-3: -Texas claimed the Rio Grande as its southern border.

Detailed explanation-4: -The Rio Grande is the fifth longest river in the United States and among the top twenty in the world. It extends from the San Juan Mountains of Colorado to the Gulf of Mexico (1, 901 miles) and forms a 1, 255 mile segment of the border between the United States and Mexico.

Detailed explanation-5: -Since 1848, the Rio Grande has marked the boundary between Mexico and the United States from the twin cities of El Paso, Texas, and Ciudad Juárez, Chihuahua, to the Gulf of Mexico. As such, crossing the river was the escape route used by some Texan slaves to seek freedom.