| Named By: | Druckenmiller in 2002 |
| Time Period: | Early Cretaceous |
| Location: | USA - Montana - Thermopolis Shale |
| Size: | Estimated around 3.5 meters long |
| Diet: | Piscivore/Carnivore |
| Fossil(s): | Remains of a single individual including the skull, vertebrae and most of a front leg |
| Classification: | | Chordata | Reptilia | Sauropterygia | Plesiosauria | Plesiosauroidea | Polycotylidae | |
Edgarosaurus is a genus of polycotylid plesiosaur, containing one species, E. muddi. The type specimen was found in Early Cretaceous (late Albian) rocks in the state of Montana in the United States. At the time, this location was covered by part of the Western Interior Seaway.