Their subsistence system included intensive hunting, collecting, and fishing. Site locations are typically on the first or second terraces along rivers and streams, and in Minnesota can be found on shores, peninsulas, and islands of shallow lakes. The Great Oasis settlement system may represent a seasonal pattern characterized by concentrated winter occupations of semi-subterranean earth lodges and dispersed summer occupations of both flood plain farming stations and mobile hunting camps. Great Oasis cemeteries appear to be located on hill or bluff tops away from the living areas, although human skeletal remains are sometimes recovered within settlement sites. Lithic assemblages are usually comprised of chert, chalcedony, and quartzite.
Projectile points are typically triangular unnotched and side notched.
Other lithic tools are similar to those of other Late Woodland and early Plains Village cultures. Some of the lithic raw material derives from distant sources such as Knife River Flint from western North Dakota and Burlington chert from southeastern Iowa suggesting developed trade networks. Bone tools also occur and include needles, awls, spatulas, quill flateners, and scapula hoes made from large mammal bones. Probably the most distinctive Great Oasis artifacts are the ceramics. Both forms are typically well made, globular jars with rounded bottoms and shoulders, constricted necks, and outflaring rims.