Flap Jack Ranch was established in 1858. By 1862 the name had changed to Grinnell's Ranch or Grinnell's Station, and that year it was also known as Stanwix Ranch or Stanwix Station.

On March 29, 1862, Stanwix Station became the location of the westernmost skirmish of the Civil War. 272 troops of the California Column, led by Capt. William P. Calloway, discovered a small detachment of ten Confederate soldiers led by 2nd Lt. John W. Swilling burning hay that was meant for the Column's horses. Gunfire was exchanged before the Confederates retreated to Tucson. There were no casualties, and only one Union soldier was injured.

In 1877, an office existed here on the military telegraph line that extended from San Diego across the Arizona Territory. Later, a station was established on the Southern Pacific Railroad, some 7 miles away, bearing the name of Stanwix.