Anglesey, or Anglesea (A.S. Angles Ey - i.e. ' the Englishmen's island'), an island and county of Wales, separated from the north-west mainland by the Menai Strait (q.v.), which is spanned by the suspension bridge (1826) and by the tubular bridge (1850). The extreme length is 21 miles; the extreme breadth, 19; the coast-line measures about 80; and its area is 302 sq. m., or 193,453 acres. The climate is mild but foggy, especially in autumn; the general aspect of the island, flat and uninteresting, there being very little wood. The island is rich in minerals; the Parys and Mona copper-mines, near Amlwch, were opened in 1768. Lead ore, containing much silver, has also been found. Anglesey, known to the Romans as Mona, was one of the chief seats of the Druidical power, which in 61 a.d. was all but destroyed by the Roman general, Suetonius Paulinus. The island was again subdued by Agricola, 76 a.d. Egbert conquered it in the 9th century, and it was finally subdued by Edward I. The market-towns are Amlwch, Beaumaris, Holyhead, Llangefni, and Llanerch-y-medd. The first four united in sending one member till 1885, when they were merged in the county, which returns one member. Pop. (1841) 38,106; (1901) 50,606.