The river that forms part of the border between the United States and Mexico is the Rio Grande, also known as Río Bravo del Norte in Mexico. It forms the natural boundary between Texas in the United States and several northern Mexican states, including Chihuahua, Coahuila, Nuevo León, and Tamaulipas, extending for about 1,255 miles along the border until it reaches the Gulf of Mexico. The Rio Grande originates in Colorado and flows through New Mexico before reaching the border area with Mexico.