Boyce Thompson Arboretum is the largest and oldest botanical garden in the state of Arizona. It is one of the oldest botanical institutions west of the Mississippi. Founded in 1924 as a desert plant research facility and “living museum”, the Arboretum is located in the Sonoran Desert on 392 acres along Queen Creek and beneath the towering volcanic remnant, Picketpost Mountain. Boyce Thompson Arboretum is on U.S. Highway 60, an hour's drive east from Phoenix and 3 miles west of Superior, Arizona.