From August 1861 to mid-1862, Tucson was the western capital of the Confederate Arizona Territory, the eastern capital being Mesilla.In 1862, the California Column drove the Confederate forces out of Arizona.In 1885, the University of Arizona was founded as a land-grant college on over-grazed ranch land between Tucson and Fort Lowell. Veterans Administration had begun construction on the present Veterans Hospital.In 1890, Asians made up 4.2% of the city's population. The population increased gradually to 13,913 in 1910. Many veterans who had been gassed in World War I, and were in need of respiratory therapy, began coming to Tucson after the war, because of the clean dry air.Jesuit missionary Eusebio Francisco Kino visited the Santa Cruz River valley in 1692, and founded the Mission San Xavier del Bac in 1700 about 7 mi (11 km) upstream from the site of the settlement of Tucson.A separate Convento settlement was founded downstream along the Santa Cruz River, near the base of what is now "A" mountain.
From 1877 to 1878, the area suffered a rash of stagecoach robberies.
In 1912, when Arizona statehood became reality, the total number of different flags that had flown over Tucson now numbered five: American, Spanish, Mexican, Confederate, and the State of Arizona.
During the territorial and early statehood periods, Tucson was Arizona's largest city and commercial center, while Phoenix was the seat of state government (beginning in 1889) and agriculture.
Eventually the town came to be called "Tucson" and became a part of the state of Sonora after Mexico gained independence from the Kingdom of Spain and its Spanish Empire in 1821. George Cooke with the Mormon Battalion during the Mexican–American War in 1846-1848, but soon returned to Mexican control as Cooke continued his mission westward establishing Cooke's Wagon Road to California.
Tucson was not included originally in the Mexican Cession and Cooke's road through Tucson became one of the important routes into California during the California Gold Rush of 1849.