Here are the details:

In 1540, the large Coronado expedition traveled along the easterned edge of Arizona in search of the legendary cities of gold (following an earlier scouting trip by De Niza and Estevan who may have been the first non-Indians to enter Arizona). They essentially claimed the whole area for Spain, but they did not stay or found any permanent settlements and after their departure, things pretty much went back to normal (with only a few rare small scouting parties) for many years.

Although the Spanish did start to establish permanent towns, forts and settlements along the Rio Grande River in New Mexico during the late 1500s, they largely stayed out of the Arizona area with the exception of a few wandering priests (the most famous being Kino) who explored the area and tried to convert the local indian populations of Arizona in the late 1600s and early 1700s. A few Spanish ranchers and prospectors might have started to explore and graze the along the current AZ-Mexico border by the early 1700s, but there were no known documented permanent mines, ranches or other outposts in Arizona until the Spanish presidio (fort) of Tubac was established in 1752. This was the first permanent official Spanish settlement in Arizona.

With an official military presence to protect them, a few ranchers and miners did start to settle in Arizona and establish a few small camps and ranches (all in the very southern portions of Arizona). In 1776, the soldiers were moved north to a new presidio at Tucson, but Tubac remained as a small town for a number of years. While explorers did occasionally wander further north, no permanent settlements or outposts were ever established beyond Tucson.

Spanish control over Arizona ended with the War of Mexican Independence (1810-21) when Mexico broke away from Spain to become its own country. Mexico assumed control of Arizona at that time. After the Mexican-American War of 1848, Mexico gave up the northern portion of Arizona (which they had no settlements in anyways) as part of the Treaty of Guadalupe Hildago, but the main settled portion (including Tucson) did not become part of the United States until it was purchased (the Gadsden Purchase) in 1856.

A couple of important notes to consider when you hear people talk about the Spanish period in Arizona:

1 – Hispanic is not the same thing as Spanish. Spanish refers to people who are official citizens of the country of Spain while Hispanic refers to anyone of Latin descent who has some ancestors that were from Spain. Citizens of Mexico after their war for independence were no longer ‘Spanish’ just as American colonists were no longer ‘British’ after the American revolution. Most Spanish people are Hispanic, but only a small portion of Hispanic people are Spanish.

2 – When hearing about Spanish missions, one needs to be aware than on the frontier, a ‘mission’ just meant a location (usually an indian village) where a priest would visit regularly to conduct mass, etc. Often times there was no permanent ‘church’ building constructed at all. The large ornate missions and associated helpers and settlers (like the famous San Xavier del Bac) were much rarer and all of the ones in Arizona were built during the later periods.