NEWBOROUGH, or NEWBURGH, a borough-town of North Wales, in the island of Anglesey, and hundred of Menai, 257 miles from London, and twelve from Beaumaris. It was once the residence of the princes of Anglesey, and a corporation founded by Edward I. There is a market, which is held on Tuesday. The population amounted in 1801 to 599, in 1811 to 750, in 1821 to 756, and in 1831 to 804.