Santiago Peak, the southern summit of the Saddleback in the Santa Ana Mountains, is the highest and most prominent peak in both the range and Orange County, making it a defining landmark of Southern California. Named for Santiago Creek and known earlier to the Acjachemen as Kalawpa, it has long dominated the surrounding landscape. The summit combines natural prominence with major modern infrastructure, hosting extensive radio and microwave facilities that serve much of five counties. It is also a popular hiking destination, with broad views of nearby mountains. In September 2024, the Airport Fire reached the peak and damaged parts of its radio facilities.