The opposing sides were rebel Magonistas and federal Mexican troops of President Francisco León de la Barra with American militia volunteers from Los Angeles, California.

Unfortunately for the Magonista cause, their leader Ricardo Flores Magon spent all of his donated revenue on propaganda in Los Angeles instead of using it to supply and arm his rebels.

The appearance of so many white men in a Mexican rebel army dissuaded the local population of Baja California to support Magon's rebellion.

At this time the Second Division was commanded by former United States Marine General John R. Mosby and consisted of 155 men, many were Industrial Workers of the World members recruited from California.

As most of the rebel troops were on foot, the movement was accomplished primarily using a work train, led by SD&A #50, a Baldwin 2-8-0 steam locomotive commandeered from the San Diego & Arizona Railway.

This strategy was failed as the out numbered rebels were poorly protected as the federals began pouring machine-gun and artillery fire from elevated positions.