10,000 B.C.: Indians inhabit Arizona.
300 B.C.: Hohokam arrive in southern Arizona and go on to build complex canal systems along the Salt and Gila rivers.
1400 A.D.: Indian settlements decline.
1528: Spanish explorers first arrive searching for the Seven Cities of Gold.
1629: Franciscans establish missions and become the first Europeans to settle in Arizona.
1776: Tucson established.
1821: Arizona becomes part of Mexico when it wins independence from Spain.
1848: Mexico cedes Arizona to the U.S., later paying $15 million for it.
1862: Arizona becomes a Confederate territory. The Battle of Picacho Pass south of Casa Grande is the westernmost battle of the Civil War.
1867: Jack Swilling, a founder of Phoenix, notices ancient canals and forms an irrigation company. Water flows in canals by the next year and rich farmland can began sustaining pioneers.
1874: Tempe founder Charles Trumbull Hayden opens the Hayden Flour Mill, which becomes one of the territory’s most important businesses.
1878: Mesa incorporates.
1881: Gunfight at the O.K. Corral. Railroads reach northern and southern Arizona.
1894: Tempe incorporates.
1912: Arizona becomes a state with a progressive constitution. Chandler is founded.
1914: Women gain the right to vote, years before national suffrage.
1920: Gilbert is incorporated, later becoming the “hay capitol of the world” and the fastest growing municipality in the U.S. through the 1990s.
1936: Hoover Dam is dedicated on the Colorado River.
1946: Arizona becomes right-to-work state.
1960: Del Webb opens Sun City, attracting 100,000 people on opening weekend and making the cover of Time. Arizona’s population reaches one million.
1961: Stewart Udall becomes U.S. Interior Secretary, the first Arizonan to hold a cabinet post.
1968: The Central Arizona Project is authorized. London Bridge arrives on the Colorado River.
1975: Raul Castro becomes Arizona’s first Hispanic governor.
1978: Apache Junction is incorporated.
1987: Pope John Paul II visits Arizona and hold mass for 75,000 in Tempe’s Sun Devil Stadium.
1988: Gov. Evan Mecham is impeached and removed from office. Rose Mofford becomes the first woman governor.
1989: Queen Creek is incorporated.
1992: Voters approve the Martin Luther King, Jr. Day holiday.
1997: Gov. Fife Symington is forced to resign after being convicted of bank fraud. The conviction was overturned in 1999 and in 2001, President Bill Clinton pardoned him.
2001: The Arizona Diamondbacks beat the New York Yankees in Phoenix, winning the World Series.
2003: Lori Piestewa is the first woman to die in the Iraq invasion. A member of the Hopi tribe, she’s also the first Native American to die in combat. Gov. Janet Napolitano stirs controversy while pushing for Phoenix’s Squaw Peak to be renamed Piewstewa Peak, but the change is made.
2011: Arizona plans a year of events leading to the centennial. Details can be found at http://www.arizona100.org.