San Luis Río Colorado

San Luis Río Colorado is a city and its surrounding municipality lying in the northwestern corner of the state of Sonora, Mexico. It is located at 32°30′N, 114°45′W, on the Río Colorado, which at this point marks the state border with Baja California. It also stands on the international border with the United States, adjacent to San Luis, Arizona. As of the 2005 census, the city had a population of 138,796 and its municipality had a population of 157,076. The city is the fourth-largest community in the state, and the municipality is also the fourth-largest. The municipality covers an area of 8,412.75 km² (3,248.2 sq mi) in the Sonoran Desert.

It is located about 20 miles from Yuma, Arizona. Because Mexico has a lower drinking age than the United States, its nightclubs are popular destinations for area high school students.

Awarded city status in July 1958, it serves as the administrative centre for the surrounding municipality of the same name. The city is located on a mesa, characterized by a flat and sandy terrain.

San Luis used to be an important inland port for steamers traveling up the Colorado from the Gulf Of California. However since the early 1900s the Colorado River in most years has been completely or nearly completely drained for irrigation use for California's valleys. Most of the time the once formidable Colorado is now dry or a small stream.