The Tonto National Forest, encompassing 2,873,200 acres, is the largest of the six national forests in Arizona and is the ninth largest national forest in the United States. The forest has diverse scenery, with elevations ranging from 1,400 feet in the Sonoran Desert to 7,400 feet in the ponderosa pine forests of the Mogollon Rim. The Tonto National Forest is also the most visited "urban" forest in the United States.

Maricopa County is in the south-central part of the U.S. state of Arizona. As of the 2020 census the population was 4,420,568, or about 62% of the state's total, making it the fourth-most populous county in the United States and the most populous county in Arizona, and making Arizona one of the nation's most centralized states. The county seat is Phoenix, the state capital and fifth-most populous city in the United States.