|View of the Rio Grande River|
The Rio Grande begins as a clear, spring and snow-fed mountain stream in Rio Grande National Forest at 3650 m (12,000 ft) above sea level and ends in the Gulf of Mexico. It is the fourth longest river system in the United States, the twenty-second longest river in the world, and is estimated to be roughly 3 million years old. It cuts through New Mexico and becomes an international boundary once it reaches the junction of Chihuahua and Texas, at the site of El Paso and Ciudad Juárez. The recognition of the Rio Grande as an international boundary comes from the Treaty of Guadalupe Hidalgo (1848) which ended the Mexican War, but the issue of the exact boundary was not solved until the banco treaty of 1905. It wasn't until the 19th century that the name Rio Grande for the whole river became the standard in the United States; previously, it was known as the Rio del Norte in the upper portions, and in Mexico, it is still usually known as the Rio Bravo. In 1997, the Rio Grande was designated as one of the American Heritage Rivers.
There is a fair amount of history associated with the Rio Grande, but rather than type it all up, I will simply redirect you to one of the cited links above for a good summary (found here).