San Luis Río Colorado: Military Colony to Border City

Just across the Arizona line into Sonora, San Luis Río Colorado is one of the youngest major cities on the US-Mexico border. On June twenty-first, nineteen seventeen, Captain Carlos G. Calles arrived on behalf of the Mexican federal government and established a military-agricultural colony on the Colorado River delta, a strategic post meant to secure the border and put the desert to work.

The Colorado River made that possible. Irrigation canals drew water from the river and converted hundreds of thousands of acres of Sonoran Desert into cotton and wheat fields. The municipality was formally recognized in nineteen thirty-nine.

Today it is a city of roughly one hundred seventy-seven thousand, planned on a strict grid with wide straight streets, and it functions as one of the key commercial crossing points between northwestern Mexico and the American Southwest.