Arizona is the 48th state and last of the contiguous states to be admitted to the Union, achieving statehood on February 14, 1912.

About one-quarter of the state is made up of Indian reservations that serve as the home of 27 federally recognized Native American tribes, including the Navajo Nation, the largest in the United States, with more than 300,000 citizens.

Harming or vandalizing saguaros in any manner, such as shooting them (sometimes known as "cactus plugging") is illegal by state law in Arizona and punishable by up to 25 years in jail. When houses or highways are built, special permits must be obtained to move or destroy any saguaro affected by the construction.

At its widest point the Grand Canyon stretches 18 miles (29 kilometers) across. At its narrowest point it stretches 4 miles (6.4 kilometers) across.

Billy the Kid killed his first victim, a blacksmith named Frank "Windy" Cahill, at a saloon in Bonita, Arizona.

The Four Corners is a region of the United States consisting of the southwestern corner of Colorado, southeastern corner of Utah, northeastern corner of Arizona, and northwestern corner of New Mexico. It is the only location in the United States where four states meet.

Some of the Painted Desert's most brilliant colors come from rocks that contain iron and manganese, which can oxidize into reddish colors. However, when the water table is high there is less oxygen in the ground, which turns these deposits blue or green.

Arizona has 13 species of rattlesnakes, more than any other state.

The state's name originates from an earlier Spanish name, Arizonac, derived from the O'odham name alǐ ṣonak, meaning "small spring", which initially applied only to an area near the silver mining camp of Planchas de Plata, Sonora. To the European settlers, their pronunciation sounded like Arissona. The area is still known as alǐ ṣonak in the O'odham language.

While the Grand Canyon might look like the perfect spot to go hunting for dinosaur bones, none have ever been found there, and for good reason. The rock that makes up the canyon walls is vastly more ancient than the dinosaurs--about a billion years more ancient, in some cases--although the canyon itself probably didn't form until after the dinosaurs were long gone. There are lots of other fossils, however, ranging from ancient marine creatures dating back 1.2 billion years to fairly recent land mammals that left their remains in canyon caves about 10,000 years ago.