Picacho Peak State Park Campground Professional Review and Guide
"Whenever we drive between Phoenix and Tucson, we always watch for the distinctive shape of Picacho Peak dancing in the distance, marking a rough halfway point. Standing 1,500 feet above the rest of the landscape, this 22-million-year-old lava spike has been a landmark for hundreds of years.
Intrepid Jesuit missionary Father Eusebio Kino noted it in the late 1600s, and in 1775 Captain Juan Bautista de Anza passed by en route to San Francisco. The Mormon Battalion, 543 men specially enlisted to fight in the Mexican War, came through Picacho Pass in 1846 on a grueling 2,000-mile trek from Iowa to California, said to be the longest military march in American history."