This list contains the toponyms (place names) in Guarani, a South American aboriginal language spoken in Paraguay, Argentina, Brazil and Bolivia.
The name of the Uruguay River deserves a special chapter, because there are several theses. Among the most accepted: "river of the snails", due to the ' (Pomella megastoma) that was plentiful across its shores. Another interpretation is "bird-river" ("the river of the uru", via Charruan, ' being a common noun for any wild fowl).