Though they were there primarily to operate against the Apaches, they were also assigned the job of reinforcing the International Line against potential incursions by the forces of the Mexican Empire and its French allies.

Shortly afterward, Sonora Governor Ignacio Pesqueira, who had fled northward after his army had been destroyed in a series of battles with the Imperialists, arrived at the post with a small party seeking refuge.

Because of its somewhat swampy (by Arizona standards) location on the banks of the Santa Cruz River, the men suffered from an epidemic which at one point rendered over half of them too sick for duty and led to at least 25 deaths.

These conditions caused construction of permanent buildings at the post to slow to a halt, leaving the men to live in tents and temporary brush shelters during their service there and generally curtailing operations against the Apaches.

The detachment found itself surrounded and under attack by a reported 100 or 200 Apaches and escaped after a fortuitous rainstorm ended a fight that lasted over an hour and left two soldiers dead and one wounded.