The battle did not begin at the Catalina River. It began in the streets of Tucson, where Apache and Navajo warriors had launched what Spanish colonial records would later call the Fourth Battle of Tucson. The raid was part of a larger pattern of conflict that had defined Arizona for decades, with indigenous warriors striking at Spanish settlements and the colonizers retaliating with increasing brutality. But this time, the Spanish were ready to pursue. As the combined Apache and Navajo force withdrew toward the mountain sanctuary they knew so well, they had no idea that a coalition of Spanish soldiers and Pima scouts was already mounting up behind them.

The pursuing force was a study in frontier cooperation born of necessity. Lieutenant Tomas Equrrola commanded forty-eight men: twelve from the remount herd guard, five Tucson citizens serving as militia, and thirty Pima scouts from the neighboring communities of Tupson and San Xavier. The Pima people had their own long history of conflict with the Apache, making this alliance of convenience grimly practical. Within forty-five minutes of leaving Tucson, this mixed force had closed the distance to their quarry. They found the Apache and Navajo warriors regrouping at the base of the Catalina Mountains, near the river that would give this engagement its name.

Faced with the oncoming Spanish and Pima force, the native army made a fateful decision. Four hundred of their 500 warriors continued their retreat up the mountain slopes, while 100 stayed behind to delay the pursuers. Among those who remained was Chief Chiquito, who had commanded the raid on Tucson. The holding action was bloody but effective. Equrrola's troops killed fourteen warriors and wounded many others, including Chief Chiquito himself. The Spanish and Pima suffered casualties too, though their exact numbers went unrecorded. Eventually the remaining rearguard was routed, but when the Spanish cavalry attempted to pursue the main force up the mountain, they found the terrain impassable for their horses.

What happened next reveals the brutal calculus of colonial warfare. The fourteen dead Apache and Navajo warriors were decapitated, their heads carried back to Tucson. There, they were mounted on the presidio walls alongside the three warriors killed during the earlier raid. Seventeen heads in total, arranged as a warning to anyone who might consider striking at the settlement again. This was not an isolated act of barbarity but standard practice in a conflict where terror served as a weapon. The Spanish hoped the grisly display would deter future raids. It did not. The Apache Wars would continue for another century.

The Catalina River that gave this battle its name has itself been largely forgotten. What Spanish colonizers called the Catalina River is now known as the San Pedro River, its waters still flowing through the same desert landscape where warriors once fought and died. The Catalina Mountains still rise to the north of Tucson, their slopes no longer a refuge for retreating war parties but a playground for hikers and astronomers. The presidio where severed heads once lined the walls became the foundation of modern Tucson, a city of over a million people who walk daily past the ground where forty-eight men once mounted up for a desperate forty-five-minute chase across the Arizona desert.