The Hanna basin is a deep, nearly circular, intermontane basin covering 2,600 km² (1,000 mi²) in Carbon and Albany Counties in south-central Wyoming. The average elevation of the basin floor is 2,150 m (7,000 ft) above mean sea level. The Hanna basin is one of the deepest structural basins in the Rocky Mountains. It contains as much as 10,800 m (35,000 ft) of sediments beginning with the Cambrian Flathead Sandstone, but the majority of the rocks are Cretaceous and Tertiary in age. The Hanna basin is surrounded by Laramide mountain ranges or uplifts: the Sweetwater arch (Seminoe and Shirley Mountains and Bennet and Freezeout Hills) on the north, the Rawlins uplift on the west, and the Medicine Bow Mountains on the south. The eastern boundary is more p orly delineated--Simpson Ridge, a small northeast-southwest-trending anticline, separates the Hanna basin from the smaller Carbon basin, which in turn is separated from the Laramie basin by the Medicine Bow anticline. The Hanna basin provides an uplift-basin couplet in which both overthrusting, at the northwest end, and largely vertical uplift at the northeast end exist almost side by side. It is proposed that, with Hanna basin is a pivot point, the extent of overhang for Rocky Mountain foreland uplifts generally increases to the north and west whereas more vertical movement dominates to the south and east. The change in structural style may be due to the rotation of the Colorado Plateau block and a thickening of the crust toward the craton. Many different types of structures are to be e countered and expected around the Hanna basin owing to the anisotropy of the basement, the sedimentary cover, and the structural forces responsible for their deformation.

The Hanna basins full hydrocarbon potential has not been realized. Several small fields are present around the basin, but deep tests are rare, especially toward the center of the basin.

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