Late Period (<1500 >years), high-altitude (>2600 m asl) archaeological sites in northwestern Wyoming prove difficult to date with traditional methods. The presence of Intermountain Ware ceramics at these sites presents an opportunity to use single-grain optically stimulated luminescence (OSL) to date vessel manufacture. These OSL ages also date site occupation as the vessels’ use-life is encapsulated within the standard error of the technique. This thesis develops a protocol to date quartz temper of Intermountain Ware sherds. Additionally, it investigates potential post-depositional thermal resetting of luminescence signals by wildfires. Ceramic sherd samples were obtained from four sites in northwestern Wyoming: Boulder Ridge, High Rise Village, Caldwell Creek, and Platt. Each site, except Caldwell Creek, has existing radiocarbon ages that provide independent age control. Additionally, all sites except Platt were impacted by past wildfires of varying intensity and consequently provide a test of the thermal resetting capabilities of wildfires.The Platt site is also the only site not located at high altitude and therefore, the sample from this site serves as a control in this study. Luminescence results demonstrate single-grain OSL dating of quartz temper from Intermountain Ware ceramics can provide improved accuracy and precision over radiocarbon dating when sherds are not adversely affected by wildfires. These results underscore the need for cultural resource managers to sample from subsurface contexts when inventorying sites impacted by high-intensity wildfires or to locate and identify sites with strong potential for high-intensity wildfires and date them prior to eventual burning. These results also validate single-grain OSL dating of ceramic temper as a valuable chronometric tool for cultural resource managers and archaeologists seeking to build and refine existing site and regional chronologies.