a borough and market-town of Anglesey, North Wales. It is situated on the bay of Beaumaris, at the northern entrance of the Menai Straits, in Lat. 53° 16' N. Long. 4° 5' W. The town consists of several neat streets, and at the extremity of the principal one stands the castle. This fortress was built by Edward I. about 1295. It covers a great extent of ground, but its imposing effect is somewhat lessened by its low position, which was so designed that the fosse might communicate with the sea, so that vessels might unload beneath its walls. The chapel dedicated to the Virgin is a spacious structure containing several fine monuments. A free school was founded here in 1603. The principal buildings are the town-hall, county-hall, prison, custom-house, assembly-room, and national school. Beaumaris has no manufactures, but is much frequented as a bathing-place. The corporation consists of a mayor, four aldermen, and nine councillors. It unites with Holyhead, Amlwch, and Llangefni, in returning a member to parliament. Market-day Saturday. The bay affords good anchorage, having seven fathoms of water at the lowest ebb. Pop. in 1851, 2399.