The name comes from a name Cuerno Verde (Green Horn) given by the Spanish of the Provincias Internas to two, father and son, Jupe Comanche band mahimiana paraibo or war chiefs. The younger Cuerno Verde was known to the Comanches as "Man Who Holds Danger." On September 3, 1779 younger Cuerno Verde, along with his son, medicine man, 4 principal chiefs and 10 of his warriors, was killed near the Greenhorn Mountain by the men of the expedition of Spanish troops and native American allies (Apache, Ute and Pueblo) under Juan Bautista de Anza.
Also Greenhorn is at the end of a small mountain range called the Wet Mountains.
A saved Google image that shows the Wet mountain range that extends from Canyon City to here. The pictures are taken looking west and is what I see where everyday.