The part of Uruguay on the Rio de la Plata is much visited for its well-preserved historic sites, pretty colonial towns, and a fair share of beaches and farmland. It includes the departments of Montevideo, Canelones, Colonia, Rio Negro, San Jose and Soriano.
Dairy farming is a major industry.
The only major airport in the region in Carrasco International Airport (IATA: MVD) just east of Montevideo. Alternatively, you can also consider flying into nearby Buenos Aires and taking a ferry from there.
Buses are available from other parts of Uruguay; Montevideo is the biggest hub by far. International buses, usually running only once or twice a week, serve Montevideo from cities including Asunción, Buenos Aires, Camboriu, Curitiba, Florianópolis, and Porto Alegre.
It's easy to drive from other parts of Uruguay or from Argentina (crossing the bridge between Gualeguaychú and Fray Bentos). If you're coming from Buenos Aires, some of the ferries will carry cars.
Ferries are available from Buenos Aires to Colonia and Montevideo, and from Tigre to Carmelo. Connecting buses are available in all of these cities, and you can sometimes choose to include a connecting bus in your ferry ticket.
Bus service is pretty extensive in the region. Montevideo is the most important hub by far, and Colonia is also a something of a hub.
This region is home to both of Uruguay's UNESCO World Heritage sites: the old city in Colonia and the meat-packing complex in Fray Bentos. Montevideo's old city is also famous. Beyond that, there are lovely little towns scattered through the region's farmland, as well as beaches on the shores of the enormous river.
Parts of the region are known for dairy production—try the cheese in Colonia del Sacramento and Nueva Helvecia!
Certain neighborhoods in Montevideo and some of its suburbs are best avoided, but other than that, the region is safe.