San Luis Río Colorado is a city and its surrounding municipality lying in the northwestern corner of the state of Sonora, Mexico.LocationIt is located at, on the Colorado River, 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. In the 2010 census, the city had a population of 159,089 and its municipality had a population of 178,380. 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 75 km from Mexicali.HistoryAwarded city status in July 1958, San Luis Rio Colorado serves as the administrative center for the surrounding municipality of the same name. The city is located on a mesa, characterized by a flat and sandy terrain. On Easter Sunday 2010, a 7.2 magnitude earthquake struck the region. The Sears department store and 5 schools were destroyed, affecting approximately 30,000 people in the region. San Luis Rio Colorado was once an important inland port for steamers traveling the Colorado from the Gulf of California. Since the early 1900s the Colorado has been completely or nearly completely drained for irrigation. The once-formidable Colorado is usually dry or a small stream.