Rio de la Plata, Uruguay January 1998 Although clouds obscure parts of the picture, the Rio de la Plata (a large estuary) is located between Argentina (south) and Uruguay (north). The estuary of the Rio de la Plata is one of the largest in the world. It receives runoff from five South American countries (Argentina, Uruguay, Brazil, Paraguay, and Bolivia). The extensive sediment plume (muddy looking water) in the Rio de la Plata seems to be a normal condition of the river. There is a constant mixing zone where the sediment-laden fresh water meets the salty waters of the southern Atlantic Ocean. Notice how a narrow band of sediment is hugging the U-shaped shoreline of the Argentina coast. The cluster of lighter colored areas near the top left corner of the image indicates the location of the city of La Plata and the eastern edge of the Argentine capital of Buenos Aires. The general location of the capital and largest city in Uruguay, Montevideo, can be identified along the northern shore of the estuary. The Santa Lucia River (dark, dendritic stream pattern) enters the Rio de la Plata just west of Montevideo