RATHMULLEN, a parish, in the barony of LECALE, county of DOWN, and province of ULSTER; containing, with the post-town of Killough (which is separately described), 2742 inhabitants. This parish, which is situated on the eastern coast and intersected by the road from Downpatrick, takes its name from an ancient rath to the south of the church, near which are still some vestiges of an ancient castle. The parish, which is bounded on the south by Dundrum bay, comprises, according to the Ordnance survey (including detached portions), 3369¾ statute acres, of which 9½ are water, and the remainder principally under tillage. A considerable tract of sand-bank extends along the shore; about 80 acres are marshy land, and there is a small portion of bog; but, with the exception of the town parks, there is very little meadow or pasture. The surface is uneven and in some parts marked by rocky elevations; but the soil in general is rich, and the system of agriculture greatly improved. Coal is supposed to exist in the lands towards the coast, but no attempt has been hitherto made to work it. A lead mine was discovered some few years since, which on examination was found to contain a large proportion of silver. Janeville, the residence of Capt. Browne, is the principal seat; there are also many excellent farm-houses in the parish. During the season, some of the inhabitants are employed in the herring and lobster fishery and a considerable coasting trade is carried on between Killough and the different ports in the channel, which is highly beneficial to the agricultural interests of the neighbourhood. St. John's Point, in this parish, is the most prominent southern headland between Dublin and the North of Ireland, and together with the adjacent bay of Dundrum has been more disastrous to shipping than any other part of the coast. From the number of wrecks that have occurred here, the erection of a lighthouse is imperatively called for, not only for the safety of trading vessels but also of the numerous fleets of fishing boats which annually rendezvous at Killough and Ardglass. This point is situated in lat. 54° 27' 40" (N.), and lon. 5° 24' 30" (W.); and a coast-guard is stationed here, which is one of the seven stations constituting the district of Newcastle. Fairs are held at Killough, as is also a monthly court for the manors of Killough, Hamilton, and Down, of which the two former are wholly within the parish. The detached townland of Rossglass was, in 1834, separated by act of council from the parish of Kilclief and united to this parish. The living is a vicarage, in the diocese of Down, and in the alternate patronage of the Earl of Carrick and Viscount Bangor; the rectory is impropriate in Viscount Bangor, Stephen Woolfe, Esq., and Miss Hamill. The tithes amount to £343. 6. 1., of which £113. 17. is payable to the impropriators, and £229. 9. 1. to the vicar. The glebe-house, towards the erection of which the late Board of First Fruits contributed a gift of £450 and a loan of £150, was built in 1817; the glebe comprises 4¾ acres, valued at £5. 18. 9. per annum. The church, a small edifice in the Grecian style, situated on an eminence overlooking the bay, was built in 1701, from the proceeds of forfeited impropriations. At Killough is a chapel of ease, the living of which is a perpetual curacy, in the patronage of the Vicar of Rathmullen. In the R. C. divisions the parish forms part of the union of Bright, and contains chapels at Killough and Rossglass. There are places of worship for Presbyterians and Wesleyan Methodists. About 250 children are taught in two public schools; and there are three private schools, in which are about 100 children, and a Sunday school: the parochial school is about to be rebuilt on a larger scale, at the expense of the vicar. There are several mineral springs, which are warm in winter and cold in summer; one is said to have a petrifying quality, equal, if not superior, to the celebrated waters of Lough Neagh. In various parts of the parish are several small forts: and on a hill to the west of the church is a cave, 34 yards in length, divided into four chambers, of which the farthest is circular and larger than the others. The headland of St. John's Point was anciently the site of a preceptory of the Knights of St. John of Jerusalem. There are still some slight remains of the church on the estate of Capt. Browne, near which several stone coffins of singular form were dug up recently, together with massive gold ornaments and curious coins; the church itself, as far as can be conjectured from its ruins, was of very singular construction, its style of architecture much resembling the Egyptian. There is also a fine spring of clear water, covered over with stones taken from the ruins of the church.
Transcribed from A Topographical Dictionary of Ireland, 1840 by Samuel Lewis