East Spanish Peak is a 12,688-foot mountain in southern Colorado, in the Spanish Peaks Wilderness of San Isabel National Forest. The lower and younger of the two Spanish Peaks, it is one of two large igneous stocks that define the range, intruded about 23.36 million years ago. Its granite porphyry core and surrounding granodiorite porphyry are thought to expose part of an ancient magma chamber after erosion stripped away higher layers. Because it stands higher than any point in the United States east of its longitude and is the easternmost U.S. summit above 12,000, 11,000, and 10,000 feet, it is a notably prominent landmark.