Situated on a peninsula on the south bank of the River Sado, bordering the city of Setúbal, to which there is a regular ferry-boat connection, Tróia retains important Roman remains, namely a fish salting plant (an important industrial complex at the time). These vestiges are testimonies of the Roman settlement of Cetóbriga, which moved to the other side of the River, and gave its name to the city of Setúbal.
Currently, Tróia is a tourist resort with excellent sandy beaches covering a total length of 18 km, as well as a wide range of hotels and a demanding golf course.
Tróia is an excellent starting point for dolphin watching.
In the Sado delta region is one of the only three sedentary communities of dolphins in all of Europe. With a population of around 30 bottlenose dolphins (Tursiops truncatus), the community is frequently seen in the waters of Setúbal and Troia.