At the time the Apache were buffalo hunting nomads and semi-nomads who had trading relationships with the Pueblos of the Rio Grande valley.

Being pushed off the buffalo-rich Great Plains into the more austere desert and mountains of the Southwest probably caused the Apache to become more dependent upon raiding for a livelihood.

They soon were also visiting Sonora and Coahuila and seem to have absorbed several other Indian peoples native to the future U.S.-Mexico border area, the Suma, Manso, Jano, and Jocome.

In 1737, a Spanish military officer said, "many mines have been destroyed, 15 large estancias [ranches] along the frontier have been totally destroyed, having lost two hundred head of cattle, mules, and horses; several missions have been burned and two hundred Christians have lost their lives to the Apache enemy, who sustains himself only with the bow and arrow, killing and stealing livestock.

The chain of 18 presidios located about 100 miles (160 km) apart in Sonora, Chihuahua, Texas, New Mexico, and future Arizona was the backbone of the defense against Apache raids.

The intensity of the conflict was at its peak from 1771 to 1776 when in Chihuahua and Coahuila "1,674 Spaniards were killed, 154 were captured, over one hundred ranches were abandoned, and over sixty-eight thousand animals were stolen."

In October and November 1775, a Spanish military operation headed by Hugo Oconór in New Mexico killed 132 Apache and took 104 prisoners.

[7] In 1786, the Viceroy in Mexico City, Bernardo de Galvez, issued an Instrución to continue war with the Apache, but also to persuade them to make peace.

Military operations intensified, but, at the same time, Apache who voluntarily surrendered and settled at the presidios were treated kindly and provided rations.

The Spanish would continue deporting Apaches to Cuba and central Mexico into the nineteenth century, a practice which Pekka Hämäläinen calls "New Spain's version of Indian removal.

The key element leading to war was that, in 1831, the Mexican government cut off food rations to Apaches settled near presidios.

[12][13] The Apache tribes most involved in the war, the Chiricahua (called "Gileños" by Mexicans) and the Mescalero numbered only 2,500 to 3,000 people.

Bands would often unite temporarily to launch larger forces against the Mexicans, but most Apache raids were relatively small scale, involving a few dozen warriors.

Most often the Apache objective in a raid was to steal livestock and other property; but a common Apache modus operandi was also to travel by horseback in small groups into Mexico, rendezvous with other groups, attack a settlement, kill the men and capture as many women, children, and livestock as desired, and then flee toward their homeland, setting ambushes along the way to discourage pursuit.

A famous and often-exaggerated battle (or massacre) involved a United States citizen named James Johnson, resident in Sonora, who led an expedition against the Apache in April 1837.

Johnson gathered together 17 North Americans and 5 Mexico muleskinners, apparently collected expense money from the Sonora government, and borrowed an artillery piece, probably a Swivel gun, small enough to be carried mule-back from the presidio at Fronteras.

The 300 to 400 inhabitants of Santa Rita fled south toward the Janos presidio, 150 miles away, but the Apache killed nearly all of them en route.

[20] In 1839 North American James Kirker was contracted by the governor of Chihuahua for 25,000 pesos to raise an army of up to 200 men to suppress the Apache.

[21] The "Sahuanos", or Shawnees, as Kirker's men were called also included Delaware Indians and escaped slaves from the U.S as well as Anglo Americans and Mexicans.

[24] It is impossible to come up with an accurate estimate of casualties for either Mexicans or Apache, but historian William E. Griffen found enough data to illustrate the scope of the war in Chihuahua.

Tucson was attacked several times and 200 people were killed by infiltrating Apache inside the walls of the presidio of Fronteras between 1832 and 1849.