Neath (Welsh: Castell-nedd) is a town and community in South Wales.

Historically, Neath was the crossing place of the River Neath and has existed as a settlement since at least Roman times, following the Roman invasion of Britannia in the 1st century AD.

The Roman writer Tacitus, in his Histories, only names three places in Wales, one of them being Neath.

Early History - There is evidence of undated settlements on the hills surrounding the town, which were probably Celtic. Human remains were discovered 25 miles (40 km) away at Paviland Cave on the Gower peninsula dated 24,000 BC proving that humans lived in the region during the last Ice Age. Once known as the "Red Lady of Paviland", the remains are those of a man. Neath was on the southern edge of the ice sheet with the Vale of Neath being a glaciated valley. Vegetation and animal life migrated to the area following the recession of the ice around 15,000 years ago.

The Romans used the name Celt (outsiders) for the unfederated European tribes outside of their empire and the inhabitants of the Neath area prior and during the Roman occupation were members of the Celtic Silures tribe. Nidum is the name of the Roman fort discovered close to a housing state, known as Roman Way, on the west side of the River Neath whereas Neath town is on the east side of the river. The fort covered a large area which now lies under the playing fields of Dŵr-y-Felin Comprehensive School.

The Roman occupation of Britain ended in the 5th century AD and at that time Christianity was spreading from the east. St Illtyd, a prominent Celtic warrior and Celtic saint who became a Christian was a major force in establishing Christianity within Wales having taught St David, the patron saint of Wales.