- Our communities, districts and Nation have a long and proud history: 1535 New Spain, including Mexico and much of the modem-day Southwest of the United States, is established.
- 1687 Father Eusebio Kino, a Jesuit missionary, arrives in Sonora. From then until his death in 1711 he builds missions and works with the Tohono O’odham and Pima, introducing Christianity, wheat, livestock, fruit, and metal tools. In 1700, he establishes the San Xavier mission.
- 1783 Construction begins on the San Xavier mission.
- 1848 The Treaty of Guadalupe Hidalgo ends the Mexican-American War with Mexico ceding most of what is now the modern-day southwest of the United States.
- 1854 The Gadsden Purchase leads to the current U.S.-Mexico border traversing O’odham lands.
- 1874 San Xavier reservation established.
- 1882 Gila Bend reservation established.
- 1917 The main Tohono O’odham reservation is established.
- 1937 The Tohono O’odham, then called the Papagos, adopt their first Constitution.
- 1970 The Tohono O’odham Utility Authority (then called the Papago Tribal Utility Authority) is created.
- 1978 Florence Village is established as part of the Nation.
- 1979 The Skill Center, later known as the Tohono O’odham Career Center, opens.
- 1983 Papago Bingo is established.
- 1986 The Tohono O’odham adopt a new Constitution establishing a three-branch form of government.
- 1993 The Tohono O’odham Nation signs its first Indian gaming compact with the state ofArizona, and Papago Bingo becomes the Desert Diamond Casino.
- 2000 Tohono O’odham Community College, which was chartered in 1998, begins offering classes.
- 2002 Archie Hendricks Sr. Skilled Nursing Facility opens.
- 2002 A new Desert Diamond Casino opens at 1-19 and Pima Mine Road.
- 2003 Land for the Hia-Ced O’odham is purchased near Why, Arizona.
- 2004 Radio station KOHN-FM 91.9 starts broadcasting.
- 2005 Recreation Centers open at five locations throughout the Tohono O’odham Nation.
- 2007 Tohono O’odham Cultural Center and Museum opens.
- 2007 The old Desert Diamond Casino is replaced by a new facility including a hotel. The Tohono O’odham Gaming Enterprise operates three casinos.
- 2007 Sells DaVita Dialysis Center dedicated.
- 2007 San Simon Health Center dedicated.
