Sines is located in the center of the Alentejo coast. It was here that Vasco da Gama was born and today it has the largest artificial harbor in Portugal.

There is evidence of human populations in the area in the county since Prehistory. Traces of some of these settlements are now discovered in archaeological sites such as Palmeirinha and Quitéria.

With the Romans, the municipality is defined for the first time as port and industrial center. The bay of Sines is the port of the town of Miróbriga. The Pessegueiro Island channel is connected to Arandis (Garvão).

The High Middle Ages, in which the region was occupied by Visigoths and Moors, and is the most obscure period in the history of Sines. There is in the Museum of Sines Visigothic stonework that attest to the existence of a basilica of the seventh century. During the southern Arab occupation of the peninsula, Sines is virtually abandoned.

It also had the Italian Naval School in the XV / XVI centuries, where they were formed naval shipbuilding engineers for the service of the kingdom, and the training of engineers for the other kingdoms of Europe.

But today through the deep water port of Sines passes more than half of the port traffic in Portugal.