Stanwix Station, in western Arizona, was a stop on the Butterfield Overland Mail Stagecoach line built in the later 1850s near the Gila River about 80 miles (130 km) east of Yuma, Arizona. Originally the station was called Flap Jack Ranch later Grinnell's Ranch or Grinnell's Station. In 1862, Grinnell's was listed on the itinerary of the California Column in the same place as Stanwix Ranch (or Stanwix Station) which became the site of the westernmost skirmish of the American Civil War. A traveler in 1864, John Ross Browne, wrote Grinnell's was six miles southwest of the hot springs of Agua Caliente, Arizona.