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,.

[1] 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.

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