The Williams Fork Formation is a Campanian to Maastrichtian (Edmontonian) geologic formation of the Mesaverde Group in Colorado. Dinosaur remains are among the fossils that have been recovered from the formation, most notably Pentaceratops sternbergii,. Other fossils found in the formation are the ammonite Lewyites, tyrannosaurids, dromaeosaurids, troodontids, nodosaurids, ankylosaurids, hadrosaurids, hybodonts, neosuchian crocodylomorphs, and the mammals Glasbius and Meniscoessus collomensis.

• List of dinosaur-bearing rock formations
  • List of stratigraphic units with indeterminate dinosaur fossils

• Weishampel, David B.; Dodson, Peter; Osmólska, Halszka, eds. (2004). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 1–880. ISBN 0-520-24209-2. Retrieved 2019-02-21.
• Diem, Stephen Daniel. (1999). Vertebrate Faunal Analysis of the Upper Cretaceous Williams Fork Formation, Rio Blanco County, Colorado [Master’s Thesis]. San Diego State University.

• Archibald, J. D. (1987). Late Cretaceous (Judithian and Edmontonian) Vertebrates and Geology of the Williams Fork Formation. N.W. Colorado. In P. J. Currie, E. H. Koster, & Royal Tyrrell Museum of Palaeontology (Eds.), Fourth Symposium on Mesozoic Terrestrial Ecosystems: Drumheller, August 10–14, 1987: Short Papers (Rev. ed, pp. 7–11). Tyrrell Museum of Palaeontology.
• Brand, N., Heckert, A., Sanchez, I., Foster, J., Hunt-Foster, R., & Eberle, J. (2022). New Upper Cretaceous Microvertebrate Assemblage from the Williams Fork Formation, northwestern Colorado, U.S.A., and its Paleoenvironmental Implications. Acta Palaeontologica Polonica, 67(3), 579–600. https://doi.org/10.4202/app.00934.2021.
• Cifelli, R. L., Eberle, J. J., Lofgren, D. L., Lillegraven, J. A., & Clemens, W. A. (2004). Mammalian Biochronology of the Latest Cretaceous. In M. O. Woodburne (Ed.), Late Cretaceous and Cenozoic Mammals of North America: Biostratigraphy and Geochronology (pp. 21–42). Columbia University Press. https://www.jstor.org/stable/10.7312/wood13040.8.
• Diem, Stephen Daniel. (1999). Vertebrate Faunal Analysis of the Upper Cretaceous Williams Fork Formation, Rio Blanco County, Colorado [Master’s Thesis]. San Diego State University.
• Noll, M. D. (1998). Sedimentology of the Upper Cretaceous Williams Fork Formation, Rio Blanco County, Northwestern Colorado [Master’s Thesis]. San Diego State University. https://digitallibrary.sdsu.edu/islandora/object/sdsu%3A17
• J. R. Foster and R. K. Hunt-Foster. 2015. First report of a giant neosuchian (Crocodyliformes) in the Williams Fork Formation (Upper Cretaceous: Campanian) of Colorado. Cretaceous Research 55:66-73
• Lockley, M. G., Smith, J. A., & King, M. R. (2018). First reports of turtle tracks from the Williams Fork Formation (‘Mesaverde’ Group), Upper Cretaceous (Campanian) of western Colorado. Cretaceous Research, 84, 474–482. https://doi.org/10.1016/j.cretres.2017.11.001.
• W. J. Kennedy, W. A. Cobban, and G. R. Scott. 2000. Heteromorph ammonites from the Upper Campanian (Upper Cretaceous) Baculites cuneatus and Baculites reesidei zones of the Pierre Shale in Colorado, USA. Acta Geologica Polonica 50:1-20
• J. A. Lillegraven. 1987. Stratigraphic and evolutionary implications of a new species of Meniscoessus (Multituberculata, Mammalia) from the Upper Cretaceous Williams Fork Formation, Moffat County, Colorado. Dakoterra 3:46-56
• Sullivan, R.M., and Lucas, S.G. 2006. "The Kirtlandian land-vertebrate "age" – faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America." New Mexico Museum of Natural History and Science, Bulletin 35:7-29.