Roper Lake State Park Hot Spring is a geothermal mineral spring near Safford, Arizona, in Roper Lake State Park. Water emerges at about 99 degrees Fahrenheit and fills a single rock-and-concrete soaking pool that can accommodate about eight people at a time. The spring is designed for easy access, with railings and vehicle access close to the pool. It is one feature of a broader state park setting that also includes camping, cabins, swimming, hiking, and fishing.