" Lough Neagh, which is the largest lake in the British islands, is chiefly in [County Antrim], but extends into several others :--it is traditionally stated to have been formed in the year 62, by an irruption of the sea, but is obviously formed by the confluence of the Blackwater, Upper Bann, and five other rivers. This lake is about 20 British miles in length from north-east to south-west, about 12 miles in extreme breadth from east to west, 80 miles in circumference, and comprises about 154 square miles : its greatest depth in the middle is about 45 feet. According to the Ordnance survey, it is 48 feet above the level of the sea at low water, and contains 98,225-1/2 statute acres, of which 50,025 are in [County Antrim], 27,355-1/2 in Tyrone, 15,556-3/4 in Armagh, 5260 in Londonderry, and 138 in Down. The only outlet is the Lower Bann, which being obstructed by weirs and rocks prevents the free egress of the waters, and causes the surrounding country to be injuriously inundated in winter. In some places the waters possess medicinal properties, which they are supposed to derive from the adjacent shore. They have also petrifying powers, but these are supposed to exist in the soil, as petrifactions are only found in the lake near the shore of [County Antrim], while they are found at considerable heights and depths and at some distance from the coast inland. Valuable hones are made of the petrified wood, and in the white sand on the shore very hard and beautiful stones, known by the name of Lough Neagh pebbles, are found : they are chiefly chalcedony, generally yellow or veined with red, susceptible of a fine polish, and highly valued for seals and necklaces. Besides the fish usually caught in fresh water lakes, Lough Neagh has the char, a species of trout called the dollaghern, and the pullan or fresh water herring. Swans, teal, widgeon, herons, bitterns, and several other kinds of birds frequent its shores. Canals connect it with Belfast, Newry, and Coal island, and a steam-boat is employed in towing trading vessels across its surface, which, although sometimes violently agitated, is scarcely ever visited by tempests, from the absence of mountains from its borders. This vast expanse of water was frozen in 1739 and 1784, and in 1814 the ice was sufficiently thick for Col. Heyland to ride from Crumlin water foot to Ram's Island, which is the only one of any importance in the lake, and contains the remains of a round tower. Sir Arthur Chichester, in 1604, received from James I. a grant of the fisheries and of the office of Admiral of Lough Neagh, which have been held by his successors and are now vested in the Marquess of Donegal. Lough Neagh gives the title of Baron to Viscount Masareene."
A Topographical Dictionary of Ireland, Comprising the Several Counties, Cities, Boroughs, Corporate, Market, and Post Towns, Parishes and Villages, by Samuel Lewis. London, England: S. Lewis, 1837.
Transcribed by Alison Kilpatrick, August 2004.