Reconstructing the depositional record of sedimentary basins is pivotal to understanding tectonic processes that influence their formation and evolution. The Paleoproterozoic Nonacho Basin in the southeastern Northwest Territories has a basin fill consisting of, from oldest to youngest, the Hjalmar, Tronka Chua, Chief Nataway, Newshethdezza, Thekulthili and Taltson formations. These units record clastic deposition in alluvial, fluvial, and marine environments during the accretion of the ancestral Canadian Shield. Presented here are the results of the summer 2021 fieldwork aimed at refining the extant stratigraphic framework of the basin. New determinations about facies variants, depositional environments, and their associated spatial lithostratigraphic relationships were elucidated by mapping traverses, stratigraphic logging (bed-by-bed logs and the first-ever stratigraphic section across a formation boundary), and detailed facies analysis. A previously inferred unconformity in the upper Nonacho Group between the Newshethdezza and Thekulthili formations is disproven in the central basin area. Furthermore, gradational contacts also occur between the Tronka Chua, Chief Nataway and Newshethdezza formations in the same area. The depositional environments of the Chief Nataway, and the overlying Newshethdezza, formations were determined to be an offshore transition zone and a channelized system, respectively. Key sedimentary structures combined with grain-size trends demonstrate a stratigraphic-upward change from proximal to distal detritus source areas followed by a return to a proximal source. Our new understanding of the stratigraphic succession, together with recent U-Pb detrital zircon data, corroborates the hypothesis that the Nonacho Basin formed due to tectonic relaxation punctuated by a period of crustal flexure. More broadly, the new field data expand the understanding of clastic sedimentation of the Rae craton's supracrustal assemblages.