Spiller Peak is a 13,123-foot mountain in the La Plata Mountains of southwestern Colorado, on the boundary of La Plata and Montezuma counties northwest of Durango. The summit is the fifth-highest point in its range and is especially steep, rising sharply above the La Plata River and Owen Basin. Its waters drain toward both the Mancos and La Plata rivers, and its high elevation gives it an alpine climate with snowy winters, summer thunderstorms, and precipitation year-round. The peak’s name was in use by 1906 and honors J. Calvert Spiller, a Wheeler Survey topographer of the 1870s associated with the first ascent and naming of Redcloud Peak in 1874.