Suuwassea (meaning "ancient thuner") is a genus of diplodocoid sauropod dinosaur found in the Upper Jurassic strata of the Morrison Formation, located in southern Carbon County, Montana, USA. The fossil remains were recovered in a series of expeditions during a period spanning the years 1999 and 2000, described by J.D. Harris and Peter Dodson in 2004. They consist of a disarticulated but associated partial skeleton, including partial vertebral series and limb bones.