An archaeological assessment was carried out on an unprovenienced human skull recovered in eastern Idaho, exhibiting cranial deformation and peri-mortem application of a red pigment. A combination of scanning electron microscopy (SEM), X-ray fluorescence (XRF), and energy-dispersive X-ray spectroscopy (EDS) identified the major and trace elements present in the red pigment as natural cinnabar. Carbon and oxygen stable isotopes from teeth and bone suggest a mostly C3 plant-based diet with subsidiary consumption of salmon or marine resources, and a regional geographic transition between early life and late adulthood. Radiocarbon dating determined the approximate age of the skull to be between 600 and 700 years old, and ancient mitochondrial DNA assessment identified characteristics of haplogroup B, one of four major Native American mitochondrial DNA lineages, which is consistent with the osteological analyses.