<p>Cinnabar, a source of red pigment, was widely used and in high demand during the Han Dynasty of China; however, its primary source and circulation remain unclear. To investigate the provenance and circulation of cinnabar during the Han Dynasty, we collected cinnabar samples from artefacts excavated from five representative Han-dynasty sites—the Haihun Marquis Tomb, Nanyue King Tomb, Mawangdui Tomb, Guankou Han Tomb, and Zonglvcheng Han Tomb—and from the modern Youyang mercury mine near the Guankou Han Tomb. We subjected both the ancient (archaeological) and modern (ore) cinnabar samples to sulfur-isotope analysis. Significant variations in sulfur-isotope values were determined for the Western Han-period cinnabar, with overlapping isotope ranges among samples unearthed from distinct sites. The sulfur-isotope compositions of the cinnabar samples from different locations indicate at least three primary cinnabar production areas during the Han Dynasty. Among these, Wuchuan in Guizhou Province was likely the most important, serving as a production hub, with Xunyang in Shaanxi Province and Xingren in southwestern Guizhou providing supplementary materials for regional cinnabar consumption. This study highlights the substantial demand for cinnabar during the Han Dynasty, which drove the formation of a widespread cinnabar circulation network.</p>