<P> When the Arizona Territory was formed in 1863 from the southern portion of the New Mexico Territory, Pima County and later Cochise County--created from the easternmost portion of Pima County in January 1881--were subject to ongoing border - related conflicts . The area was characterized by rapidly growing boom towns, ongoing Apache raids, smuggling and cattle rustling across the United States - Mexico border, growing ranching operations, and the expansion of new technologies in mining, railroading, and telecommunications . </P> <P> In the 1860s conflict between the Apaches and the Americans was at its height . Until 1886, almost constant warfare existed in the region adjacent to the Mexican border . The illegal cattle operations kept beef prices in the border region lower and provided cheap stock that helped small ranchers get by . Many early Tombstone residents looked the other way when it was "only Mexicans" being robbed . </P> <P> Outlaws derisively called "The Cowboys" frequently robbed stagecoaches and brazenly stole cattle in broad daylight, scaring off the legitimate cowboys watching the herds . Bandits used the border between the United States and Mexico to raid across in one direction and take sanctuary in the other . In December 1878, and again the next year, Mexican authorities complained about the "Cowboy" outlaws who stole Mexican beef and resold it in Arizona . The Arizona Citizen reported that both U.S. and Mexican bandits were stealing horses from the Santa Cruz Valley and selling them in Sonora . Arizona Territorial Governor Frémont investigated the Mexican government's allegations and accused them in turn of allowing outlaws to use Sonora as a base of operations for raiding into Arizona . </P> <P> In the 1870s and 1880s there was considerable tension in the region - between the rural residents, who were for the most part Democrats from the agricultural South, and town residents and business owners, who were largely Republicans from the industrial Northeast and Midwest . The tension culminated in what has been called the Cochise County feud, and the Earp - Clanton feud, which ended with the historic Gunfight at the O.K. Corral and Wyatt Earp's Vendetta Ride . </P>

Increased u.s. territory in present-day arizona and new mexico