how far back can the human settlement there be traced?
Continuous human habitation dates from the end of the last ice age, between 12,000 and 10,000 years before
Wales
Continuous human habitation dates from the end of the last ice age, between 12,000 and 10,000 years before present (BP), when Mesolithic hunter-gatherers from central Europe began to migrate to Great Britain. 
what is neath and tennant canal? They are two independent but linked canals in South Wales that are usually regarded as a single canal. when were they restored? They are the subject of active restoration projects. what is the purpose of these canals? It provided better facilities for transferring cargo to ships. where is it located? South Wales
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Wales [SEP] Prehistoric origins
Over the following centuries they assimilated immigrants and adopted ideas from Bronze Age and Iron Age Celtic cultures. Some historians, such as John T. Koch, consider Wales in the Late Bronze Age as part of a maritime trading-networked culture that included other Celtic nations. This "Atlantic-Celtic" view is opposed by others who hold that the Celtic languages derive their origins from the more easterly Hallstatt culture. By the time of the Roman invasion of Britain the area of modern Wales had been divided among the tribes of the Deceangli, Ordovices, Cornovii, Demetae and Silures for centuries.