From Samuel Lewis's Topographical Directory of Ireland.

NEWCASTLE, a small sea-port town, in the parish of KILCOO, barony of UPPER IVEAGH, county of DOWN, and province of ULSTER, 3 1/2 miles (S. E.) from Castlewellan; containing 987 inhabitants.

This place, which is situated on the shore of Dundrum bay, in the Irish sea, derives its name from a castle erected here by Felix Magennis, in the memorable year of the Spanish Armada; and though only an inconsiderable fishing village previously to the year 1822, it has since been gradually increasing in importance.

In addition to its trade as a port, it has made great advances as a fashionable place for sea-bathing, and is now nearly a mile in length, containing several large and handsome private dwelling-houses, and numerous comfortable and respectable lodging-houses.

The castle, built by Magennis close to the sea shore, has been taken down, and on its site Earl Annesley has erected a spacious and elegant hotel, from a design by Mr. Duff, of Belfast, at an expense of £3000, which is fitted up with superior accommodations, including hot and cold baths, and every requisite arrangement.

The house is beautifully situated and commands a most extensive prospect, embracing the isle and calf of Man in the foreground, and in the rear the lofty mountains of Mourne. Earl Annesley has also built an elegant marine residence, called Donard Lodge, at the foot of Slieve Donard; the demesne is laid out with great taste, and within its limits is a chalybeate spa, to which the public has free access.

The other seats are Tollymore, the residence of Mrs. Keowen, situated near the town; Brook Lodge, of W. Beers, Esq.; and the residence of John Law, Esq., a handsome mansion in the Elizabethan style.

The environs are of pleasing character, and abound with interesting scenery; they afford many agreeable walks and rides, and within two miles of the town are Tollymore Park, the handsome seat of the Earl of Roden, and the beautiful village and church of Bryansford.

The trade of the port consists chiefly in the export of oats, barley, and potatoes, of which large quantities are sent to Dublin and Liverpool. A commodious pier has been erected on an extensive scale, at an expense of £30,000; it is accessible at high water to vessels of large burden, and has been very beneficial to the trade of the town.

Granite of very fine quality abounds in the neighbourhood; the quarry was first opened, in 1824, by J. Lynn, Esq., and the stone is conveyed from the mountain by a rail-road to the pier, and large quantities of it are shipped.

From this quarry was raised the stone for the court-house, new prison, infirmary, and fever hospital of Downpatrick, the chapel of ease in this town, and the spire of Inch church.

Newcastle is the head of a coast-guard district, which extends from Strangford to Warren Point, including the stations of Gun Island, Ardglass, St. John's Point or Killough, Leestone, and Cranfield, comprising a force of one resident inspector, seven officers, and 66 men.

A penny post has been established to Castlewellan, and a constabulary police force has been stationed here. The chapel of ease is a handsome building, with a spire at the east end; it was erected at an expense of £1500 by Earl Annesley, who pays the curate a stipend of £100.

In the mountains and streams near the town are found fine specimens of rock crystal, of the various hues of beryl, emerald, amethyst, and topaz, some of which have brought high prices.

Sand eels are found in great numbers on the beach at particular seasons.

Within a mile and a half is a place called the Giant's steps, near which is a cavity of great depth, resembling the shaft of a mine, and called Armour's Hole, from the circumstance of a man of that name having been thrown into it, whose body was found next day at St. John's Point, about ten miles distant.

At a small distance from it is a cavern resembling a tunnel, supposed to have been excavated in the rock by the incessant action of the waves.