Phandalin was believed to have been established centuries ago, during the Tiberian Age, but was destroyed by the Creeg a century or so ago. The town is being resettled as the power of Neverwinter swells.
From the starter set"
“In the last three or four years, hardy settlers have been rebuilding another ruin near the city: the old town of Phandalin, which orcs sacked five centuries ago. Clearly, what Phandalin needs now is a civilizing influence—someone to take the reins and bring law and order.”