Flagstaff lies near the southwestern edge of the Colorado Plateau, along the western side of the largest contiguous ponderosa pine forest in the continental United States. Flagstaff is located adjacent to Mount Elden, just south of the San Francisco Peaks, the highest mountain range in the state of Arizona. Humphreys Peak, the highest point in Arizona at 12,633 feet (3,851 m), is located about 10 miles (16 km) north of Flagstaff in Kachina Peaks Wilderness.
Flagstaff's early economy was based on the lumber, railroad, and ranching industries. Today, the city remains an important distribution hub for companies such as Nestlé Purina PetCare, and is home to Lowell Observatory, The U.S. Naval Observatory, the United States Geological Survey Flagstaff Station, and Northern Arizona University. Flagstaff has a strong tourism sector, due to its proximity to Grand Canyon National Park, Oak Creek Canyon, the Arizona Snowbowl, Meteor Crater, and historic Route 66. The city is also a center for medical device manufacturing, since Flagstaff is home to W. L. Gore and Associates.
There exist several stories and legends regarding the origin of the city's name. Surveyors, prospectors, and investors had traveled through the area in the mid- to late-19th century, and the act of stripping a pine tree to fly an American flag has been attributed to several individuals over the course of a twenty-year span. It is said that, because of the flag that was raised, the area surrounding it became known as Flagstaff.
The first permanent settlement was in 1876, when Thomas F. McMillan built a cabin at the base of Mars Hill on the west side of town. During the 1880s, Flagstaff began to grow, opening its first post office and attracting the railroad industry. The early economy was based on timber, sheep, and cattle. By 1886, Flagstaff was the largest city on the railroad line between Albuquerque and the west coast of the United States. A circa 1900 diary entry by journalist Sharlot Hall described the houses in the city at the time as a "third rate mining camp", with unkempt air and high prices of available goods.
In 1894, Massachusetts astronomer Percival Lowell hired A. E. Douglass to scout an ideal site for a new observatory. Douglass, impressed by Flagstaff's elevation, named it as an ideal location for the now famous Lowell Observatory, saying: "other things being equal, the higher we can get the better". Two years later, the specially designed 24-inch (610 mm) Clark telescope that Lowell had ordered was installed. In 1930, Pluto was discovered using one of the observatory's telescopes. In 1955 the U.S. Naval Observatory joined the growing astronomical presence, and established the United States Naval Observatory Flagstaff Station, where Pluto's satellite, Charon, was discovered in 1978.