National Gazetter 1868
AMLWCH, a parish, market town, and parliamentary borough in the hundred of Twrcelyn, in the Isle and county of Anglesey, North Wales, 15 miles to the N.W. of Beaumaris, 20 miles to the N.E. of Holyhead, and 261 miles from London. It is situated on the northern coast of the island, on the Irish Sea, and its port is subordinate to Beaumaris. It includes the two chapelries of Llanwenllwyfo and Llanerchymedd. Its present importance and prosperity are of very recent and rapid growth.
Previous to the year 1768, Amlwch was a mere fishing village, of very inconsiderable extent. In that year the now celebrated copper mines of the Parys mountain were discovered, and the foundation for the future wealth and progress of the town was laid. The native name of this mountain is Trysclwyn, and its more familiar name is said to be derived from Robert Parys, one of the commissioners appointed by Henry IV., on occasion of the insurrection under Owain Glyndwr. In the most favourable years, above 60,000 tons of ore have been taken from these mines, and 1500 hands were employed in them. After a period of decline the works are now carried on again, and give employment to about 1000 hands.

There are several interesting proofs that the mineral wealth of the Parys mountain and its neighbourhood attracted attention at a remote period. It was probably known to the Romans, and still earlier to the Phoenicians. The Marquis of Anglesey and Lord Dinorben are the proprietors of the mines. A noble harbour has been constructed by the companies who work the mines. It is cut out of the slate cliff; and is large and deep enough to hold thirty vessels, of 200 tons burden. It is protected by a breakwater, erected in 1822, and its bed is dry at low water. There are several dangerous rocks lying near the entrance to the harbour. A lighthouse; 26 feet high, has been erected on the north pier. It has a fixed light, which is visible at a distance of 9 miles. There are several smelting furnaces, employing about 100 persons, and some alum and vitriol works.

The living is a perpetual curacy* in the diocese of Bangor, value £217, in the patronage of the bishop. The church is dedicated to St. Elaeth; it is large enough to hold 2000 persons, and was built in 1800, by the proprietors of the mines. There are chapels belonging to the Baptists Independents, Calvinistic and Wesleyan Methodists. A school was founded and endowed, in 1689, by Edward Kynnier, for poor children. The endowment, since 1821, has been applied in aid of the support of the national school then established. A British school for 400 children, of both sexes, was founded in 1860. Under the Reform Bill, Amlwch was made a contributory borough with Holyhead and Llangefni, to Beaumaris, and with them returns one representative to parliament. A branch of the National Provincial Bank was established here in 1859. A fair for cattle is held on the 12th November. "

"PARYS, a rich copper mine in the mountain of the same name, in the parish of Amlwch, hundred of Twrcelyn, county Anglesey, 15 miles N.W. of Beaumaris. The copper mine, which belongs to the Marquis of Anglesey, was at one time much richer than at present, producing 70,000 tons of copper ore, worth a quarter of a million, a year."

[Description(s) from The National Gazetteer of Great Britain and Ireland (1868)