Data set containing results from constant mean stress - constant Lode angle true triaxial compression tests performed on Castlegate Sandstone. From the test preformed, the bedding plane and the strain type inside the band of sedimentary rocks can be related to stress histories. The goal of these tests are to understand the conditions that lead to localized deformation in porous sandstone which has geotechnical applications such as oil and natural gas production, carbon dioxide sequestration, and hazardous waste storage.