The Three Forks Formation of Montana, North Dakota, and Manitoba and the equivalent Torquay Formation in Saskatchewan is a new oil resource play. Although it is part of the Bakken Petroleum System, it is geologically distinct from the Bakken and has its own complex geological history. This study incorporates core logging, log correlations, and laboratory analysis, which led to the development of detailed facies and stratigraphic models, reservoir characterizations, a petrophysical model, and a hydrogeological model of the Three Forks. The study covers the area from T.135N, R.75W in North Dakota (southeast) to T. 8 R.16W2 in Saskatchewan (northwest). The study focuses on the Late Devonian-aged Three Forks Formation in the US, and the equivalent Torquay Formation in Canada. It also includes the Big Valley Formation and the basal transgressive unit of the Bakken Formation. There are 55 cores described in the study. Over 500 core photos were taken and 99 samples were selected for thin-section analysis. Twenty-four samples were picked for XRD analysis. A total of 2,374 wells were correlated into the stratigraphic model and 12 regional cross-sections were constructed to illustrate these picks. The LAS files for 174 wells were acquired and petrophysically analysed, from which the reservoir maps were constructed. All the available DSTs were screened, from which 58 reservoir pressures were obtained for the Three Forks hydrogeological analysis.