Cinnabar ore is the source of a bright red pigment (mercury [II] sulfide, HGS), a substance that was highly valued in the Central Andes during prehispanic times. It is traditionally believed to come from Huancavelica in south-central Peru, although some scholars have argued that a prehispanic cinnabar source existed at Azogues near Cuenca in southern Ecuador. It has also been suggested that the cinnabar recovered at archaeological sites in northern Peru such as Baton Grande may have come from this putative Ecuadorian source. In this article, the historical and archaeological evidence supporting this position is evaluated and found to be insufficient to sustain the Ecuadorian Cinnabar Hypothesis. Moreover, recent mercury isotope analysis of archaeological samples from northern Peru supports the earlier hypothesis that the source of the bright red pigment, sometimes referred to as vermilion, was cinnabar ore mined in Huancavelica. This source is located over 850 km to the south of archaeological sites such as Batdn Grande, Chongoyape, and Pacopampa.