LOUDOUN, or Loudon, a parish, in the district of Cunninghame, county of Ayr, 8 miles (E.) from Kilmarnock; containing, with the village of Darvel, and the burgh of barony of Newmilns, about 5550 inhabitants. This place is supposed by some to take its name, the first syllable of which signifies a " fire", and the second a "hill", from a hill in the extremity of the parish, which, on account of its commanding height, is conjectured to have been used as a station for signal-fires. Others, however, derive the name from the Gaelic term Lod-dan, signifying "marshy ground", the land in the vicinity of the river Irvine, on the south, having formerly possessed this character. The parish approaches in figure to a right-angled triangle, the greatest length being about eight or nine miles, and the average breadth three. It stretches on the east to the county of Lanark, and comprises 19,169 acres, of which 10,720 are in tillage, 3153 bent and moor pasture, 882 in plantations, and the rest moss. The Irvine, rising in the north-eastern corner, flows in a direction nearly south for about two miles, separating Loudoun from Avondale parish in Lanarkshire; after which, sweeping round the towering hill of Loudoun, it pursues its picturesque course to the west, dividing the parish from that of Galston. The system of agriculture is advanced, and the crops are of excellent quality. Great improvements have been made within the last few years on the Loudoun property, comprising chiefly the erection of very superior farm-houses and the construction of roads. Large tile- works have been in operation some years; and other works of the same kind have lately been erected near the village of Darvel, which are intended to supply tiles for public sale. The coal formation is to be seen in almost every part of the parish; but it is so much disturbed by the trap rock as to be in some places incapable of being worked: the trap, of which the columnar trap composing Loudoun hill is a portion, forms part of a large trap-dyke running through the whole Ayrshire coalfield in a north-west and south-east direction. There are also several seams of ironstone, some of them of considerable thickness; and these, as well as the coal, are expected shortly to be wrought. Limestone is abundant, and is extensively quarried; a bed at Howlet burn, about six feet thick, is wrought by mining, and is at present let to the Cessnock Iron Company for smelting purposes. The annual value of real property in the parish is £96/9. Loudoun Castle was the seat of the ancient family of Campbell, Earls of Loudoun, a title now merged in that of the Marquess of Hastings, the present proprietor of Loudoun. This fine baronial residence, which was mostly rebuilt after its destruction by fire about the beginning of the sixteenth century, has some old portions; but the larger and more splendid part of the structure was completed in 1811. One of the square towers, with its battlements of unknown antiquity, was destroyed when the castle was besieged by Genera! Monk; but another tower, larger and higher, built in the fifteenth century, still remains in good condition. There is an excellent library containing upwards of 11,000 volumes. The plantations around the castle comprise a great variety of trees, some of them brought from America by John, fourth Earl of Loudoun, who was governor of Virginia in 1756, and who, during his military services in various parts of the world, sent home every valuable kind of tree he met with. He formed an extensive collection of willows, selected from England, Ireland, Holland, Flanders, Germany, Portugal, and America; and a laurel, brought from Portugal, covers with its branches a space 140 feet in circumference. In the grounds of the mansion is also a yew-tree of great antiquity, still fresh and vigorous, and under the shade of which, one of the family charters, it is said, was signed in the time of William the Lion; as also one of the articles of the Union by Hugh, third earl. The parish contains the villages of Newmilns and Darvel, and the hamlets of Auldton and Loudoun- Kirk; the first of which is a burgh of barony, and, as well as Darvel, has a large population, a great proportion of whom are weavers. Another branch of manufacture is wool-spinning, at a mill established in 1804, and belonging to a company of carpet manufacturers in Kilmarnock: about twenty-five hands are at work. The agricultural produce is sent for sale to Kilmarnock, and coal is generally brought from pits three miles distant. In 184" an act of parliament was passed authorising the Glasgow and Ayrshire railway company to make a branch of nearly three miles and a half to Loudoun-Kirk. Ecclesiastically the parish is in the presbytery of Irvine, synod of Glasgow and Ayr, and in the patronage of the Marquess of Hastings: the minister's stipend is £191, with a manse, and a glebe of sixteen acres, valued at £35 per annum. The church, situated in the village of Newmilns, is a splendid structure erected in 1844, with sittings for 1'200 persons, and ornamented with a beautiful steeple 133 feet in height. There is a place of worship at Newmilns belonging to the United Presbyterian Synod, and another at Uarvel for Reformed Presbyterians. The parochial school, also at Newmilns, affords instruction in the usual branches; the master has a salary of £34. 4., with a house and garden, £40 fees, and £10, the interest of a be(|uest of £200. There arc schools at Darvel and Auldton, the schoolrooms and dvvelling- houses being provided by the Loudoun family; and at Newmilns are two female schools, one of them supported partly by subscription. The parish has three libraries, a masonic society, and two or three other friendly societies; also three charities, one, amounting to £60 per annum, for decayed burgesses of Newmilns, left by Mr. James Smith, a native of that place; another, a bequest of £16 per annum for four old people, by Mrs. Crawfurd; and the third, a legacy by Mr. Brown, of Waterhaughs, for the education and clothing of twelve children. The principal remains of antiquity are, the foundations of a Druidical temple, on the top of a hill the highest in the parish except that of Loudoun; the ruins of a castle burnt by the Kennedys, probably in the time of James VI.; and a small ancient castle at Newmilns. In the east of the parish is Wallace's Cairn, marking out the scene of a conflict between Wallace and a party of English whom he surprised on their way to Ayr with provisions; and at a pass, which is traversed by the road, the battle of Loudoun Hill was fought in 1307, between Bruce and a body of English troops under the Earl of Pembroke. The parish is, however, chiefly remarkable for its connexion with the ancient family of Campbell, long resident here, and of whom Lambrinus, father of James de Loudoun, possessed the barony in the reign of David I. The first earl, who was buried in the church of Loudoun, was chancellor of Scotland in 1641, and acted a prominent part in the transactions of that eventful period. His grandson, the third earl, was also of some consideration, enjoying the confidence of William III., and holding the office of an extraordinary lord of session. Flora, Countess of Loudoun, only child of James, fifth earl, in 1804 married the Earl of Moira, who was raised to the dignity of Marquess of Hastings in 1816, in acknowledgment of his highly distinguished services. This lady, who was the mother of the lamented Lady Flora Hastings, died in 1840, and was succeeded by her only son, George, sixth Earl of Loudoun and second Marquess of Hastings, whose decease occurred in the year 1844, when his only son, born in 1832, succeeded to the titles and estates. Lady Flora Hastings, whose sufferings and wrongs excited so deep a sympathy throughout the whole nation, was buried in the family crypt at the hamlet of Loudoun- Kirk, near Loudoun. See Darvel, and Newmilns.