The Kisseynew Gneisses occupy a large structural basin which can be traced from Reindeer Lake to Kisseynew Lake in Saskatchewan, and for at least 70 mi (113 km) east of the provincial boundary with Manitoba. The domain is flanked on the south and west sides by metavolcanics and metasediments of the Amisk Series, and by their presumed equivalents of a higher metamorphic grade. The northern boundary is composed of foliated granodiorites.The rocks have been assigned to two lithological groups, the Nokomis and the Sherridon, which correspond to similar divisions of the Kisseynew gneisses in Manitoba. The Nokomis is predominantly a graphite bearing pelitic gneiss containing cordierite and sillimanite, with subsidiary amphibole bearing gneisses and calc-silicates. It is characterized by a low aeromagnetic relief (< 61 300 γ). The Sherridon, by contrast, is characterized by a higher aeromagnetic signature (61 300–62 350 γ), being a magnetite bearing semi-pelitic gneiss.The Kisseynew basin has a complex structure resulting from three phases of deformation. Large recumbent and reclined folds formed in the first period of deformation have been refolded during a second period of deformation producing complex interference patterns. A third phase of deformation produced a series of regional elbow-like folds with east–northeasterly trending axial surface traces.