In 1876, the Boston Party, a group of men who had been lured west, made camp in a mountain valley on the Fourth of July. They stripped a pine tree of its branches and hung a flag at its top. Afterward, the tree was used as a marker for travelers who referred to the place as the spring by the flag staff. In 1882, Flagstaff became a railroad town when the Atlantic and Pacific Railroad (now the Santa Fe) was built.

Flagstaff, home of Northern Arizona University (1899), is an educational and cultural center. Tourism is Flagstaff's main industry; the city is a good place to see the Navajo country, Oak Creek Canyon, the Grand Canyon, and Humphreys Peak (12,670 feet), the tallest mountain in Arizona. Tall pine forests of great beauty abound in the surrounding area. A Ranger District Office of the Coconino National Forest is located here.