d. Rio Grande River
The Rio Grande, with a length of 1,890 miles approximately and beginning in South-central Colorado of the U.S. is a river that marks the division between the American state of Texas and the Mexican states of Chihuahua, Coahuila, Nuevo León, and Tamaulipas. It's also part of the boundary between the U.S. states of New Mexico and Texas. Certainly, Rio Grande is a river that makes up some of the western borders of Texas.