Organ Pipe Cactus National Monument celebrates the life and landscape of the Sonoran Desert. Here, in this desert wilderness of plants and animals and dramatic mountains and plains scenery, you can drive a lonely road, hike a backcountry trail, camp beneath a clear desert sky, or just soak in the warmth and beauty of the Southwest. The Monument exhibits an extraordinary collection of plants of the Sonoran Desert, including the organ pipe cactus, a large cactus rarely found in the United States. There are also many creatures that have been able to adapt themselves to extreme temperatures, intense sunlight and little rainfall. Acreage: 330,688.86; Federal: 329,316.31; Non-federal: 1,372.55. Wilderness area: 312,600.