Río La Leona is the name given to a fossil site located on the Eastern Bank of the La Leona River in Southwestern Santa Cruz Province, Argentina.
The area of La Leona was explored and named by Francisco (Perito) Pacasio Moreno, an Argentinian scientist and explorer.
This specific fossil site is part of the Cerro Fortazela Formation, which has been dated to the Campanian to Maastrichtian ages of the Late Cretaceous. Titanosaurs, megaraptors, and an ornithopod (along with non-dinosaurs) have been found in the Cerro Fortazela Formation. This specific site has yielded two specimens of Dreadnoughtus schrani.
The site gains its name from Río La Leona, meaning "River of the Lioness". The river was given its name in 1877 by Perito Moreno after he was attacked by a female puma while camped along the river.