Oplontis is an ancient Roman archaeological site, located in the town of Torre Annunziata, south of Naples in the Campania region of southern Italy.

Among the finds in the western zone, the most important is the Roman bath complex on the sea shore at Oncino (the Terme Nunziante) as a public building of Oplontis.

[5] R. Liberatore recorded the archaeology in detail[6] and he identified it as belonging to Lucius Nonius Florus whose name is stamped on the edge of a terracotta basin in the baths, decorated with vegetal forms and galloping horses.

In 1785 the Spanish architect Francesco La Vega explored this area, known as Le Mascatelle, with tunnels and found beautiful objects but soon gave up due to toxic gases.

In 1839–40 excavations in tunnels were restarted by Michele Rusca using La Vega's publications and he discovered for the first time the extent and quality of the building including two peristyles, mosaics and other decorations.

From 1880 a series of mills and pasta factories were built in Via Fontanelle in the Oplontis area and ancient Roman walls, marble columns, mosaic pavements, and many fragments from a variety of objects were found in their foundation trenches.

[10] In 1975 the only human skeleton was found at the northern edge of the site, an adult lying on its back 6 m above the floor of the villa who must have been carried by the volcanic flow probably from farther inland.

Villa A was probably uninhabited and still in the process of being rebuilt at the time of the AD 79 eruption, as a number of tools were found on the site and statues and columns were stored away from their proper places.

On the south side of the courtyard eight barrel-vaulted storerooms were added after 50 BC, supporting well-decorated rooms above in the Fourth Style, facing the sea and opening onto a large portico, perhaps the owner's living quarters.

[14] This villa was not deserted at the time of the eruption: the remains of 54 people were recovered in one of the rooms facing the sea, probably waiting to escape but perishing in the surge that hit Oplontis.

[16] The "lady of Oplontis" was discovered with a bronze jug (for water in those last hours), a purse and a small basket, containing coins and jewellery and near her stomach was a string of cheap blue pottery beads.

It was finely decorated with inlay in silver, copper, and gilded bronze typical of late Hellenistic design, and had a complex locking system that was still used in the 19th century.