The Río Conchos is the Rio Grande's most important Mexican tributary, draining a vast area of Chihuahua state. It meets the Rio Grande a few kilometres east of Ojinaga at a point locally called La Junta de los Ríos — "the joining of the rivers" — a name that goes back to the Spanish colonial period when this confluence was a significant landmark on the Camino Real trade route.
The confluence is notable for a depressing reason as well as a scenic one: the Rio Grande above this point is so heavily dammed and diverted that it often runs dry by the time it reaches Ojinaga. The water you see continuing downstream into Texas is mostly Conchos water, not Rio Grande water. The desert landscape around the joining is striking — flat scrubland giving way to the canyon country that begins a little further downstream in Big Bend.