This bulletin describes the surficial geology and Quaternary history of the Stevenson Ridge and northern Kluane Lake map sheets, an area covering more than 12 000 square kilometres of southwestern Yukon. The map area straddles the Pleistocene glacial limits that formed the eastern margin of Beringia during glacial periods. As a result, the landforms of this region are diverse and reflect the contrasting geomorphology characteristic of glaciated versus unglaciated terrain. Importantly, work in this region filled a significant gap in our knowledge of central Yukon glacial limits and how adjacent landscapes were impacted by the Cordilleran Ice Sheet. Our goal was to produce an in depth description of the region’s surficial geology that is applicable for a wide range of purposes. While this region is remote, there is growing interest in its mineral endowment, specifically in the Dawson Range, east of the White River, and in the Ruby Range. Knowledge of the surficial geology can be employed in exploration geochemistry programs to improve sampling and can assist in placer exploration. Future development in the region will also benefit from this work by providing a framework on terrain hazards, such as permafrost and landslides, and construction materials like aggregate. From a land use planning perspective, the surficial sediments and associated soils are an important control on the region’s biogeography and therefore, habitat. Hundreds of soil pits were hand excavated during this program and this work is reflected in the detailed descriptions within the bulletin and on the maps.