Colonia Carlos Pellegrini is a small town and municipality in San Martín Department in Corrientes Province, Argentina. It was established in 1927. It is connected by road to Mercedes in the southwest. It lies within the Iberá Provincial Nature Reserve (Reserva Natural Provincial del Iberá, also known as the Iberá Wetlands), a wetland of 1,300,000 hectares on a peninsula that enters the Iberá lagoon 5,500 ha. It has diverse wildlife, including alligators, swamp deer and over 350 species of birds.