Ciudad de la Costa is a city in Canelones Department of Uruguay, on the banks of the Río de la Plata between the streams Arroyo Carrasco and Arroyo Pando. It is considered an extension of the metropolitan area of Montevideo which it borders to the west, while to the east it borders Costa de Oro. It was declared a city on 19 October 1994 and given its current name. At the 2011 census, it was the second most populated city of Uruguay between Montevideo and Salto.

The Río de la Plata, also called the River Plate or La Plata River in English, is the estuary formed by the confluence of the Uruguay River and the Paraná River at Punta Gorda. It empties into the Atlantic Ocean and forms a funnel-shaped indentation on the southeastern coastline of South America. Depending on the geographer, the Río de la Plata may be considered a river, an estuary, a gulf, or a marginal sea. If considered a river, it is the widest in the world, with a maximum width of 220 kilometres (140 mi).