Stretching west along the Río de la Plata from Montevideo are the agricultural and dairying departments of San José and Colonia. To the north along the Río Uruguay lie the departments of Soriano, Río Negro, and Paysandú. Their western halves form part of the littoral, a region that is somewhat more developed than the interior. Here soils are alluvial and more fertile, favoring crop production and farms of more modest size than in the interior. Citrus cultivation for export has increased in the departments along the Río Uruguay. The department of Colonia, some of which was settled by the Swiss, was famous for the production of milk, butter, cheese, and dulce de leche (a dessert made from concentrated milk and sugar). Most wheat (in which Uruguay was self-sufficient) also was produced in this region.

Construction with Argentina of the Salto Grande Dam across the Río Uruguay north of Salto was a major boost to the development of the northern littoral in the 1970s. By contrast, the closure of the famous meat-packing plant at Fray Bentos in the department of Río Negro transformed it into a virtual ghost town. Farther south, the littoral economy had benefited from completion of the General Artigas Bridge across the Río Uruguay from Paysandú to the Argentine province of Entre Ríos. However, the advent of a convenient (if circuitous) land route from Montevideo to Buenos Aires via the new bridge reduced freight and passenger traffic through the small port of Colonia on the Río de la Plata just opposite the Argentine capital. To compensate, the Uruguayan government encouraged the architectural restoration of Colonia, which was originally built by the Portuguese in colonial times. In 1990 Colonia had became one of Uruguay's most historic tourist attractions, and many of its houses had been bought by vacationers from Buenos Aires.

Data as of December 1990