The Circuito Sur de Oriente (CSO), meaning "Southern Circuit of the Orient", is a west-east highway connecting Bayamo to Santiago de Cuba, through Manzanillo, Niquero and the southern coastal side of eastern Cuba, below the Sierra Maestra mountain range. Also known as Circuito Guacanayabo-Sur de Oriente, because it crosses the Gulf of Guacanayabo, the name Oriente, refers to the ancient and former Oriente Province. With a length of 347 km, it is the fourth-longest Cuban highway after the "Carretera Central", the "Circuito Norte" and the "Circuito Sur".

Manzanillo is a municipality and city in the Granma Province of Cuba. By population, it is the 14th-largest Cuban city and the most populated one not being a provincial seat.