CASTLEMARTYR, a post-town (formerly a parliamentary borough), partly in the parishes of ITERMORROUGH, BALLYOUGHTERA, and MOGEELY, barony of IMOKILLY, county of CORK, and province of MUNSTER, 19 miles (E. by N.) from Cork, and 127 (S. W. by S.) from Dublin; containing 830 inhabitants. This place is situated on the road from Youghal to Midleton, and on the mail coach road from Dublin, by Waterford to Cork; it appears to have risen into importance at a very early period. At the time of the English invasion, the castle, then called the castle of Imokilly, was resolutely defended by one of the Geraldines; but the English at length reduced it and kept in it a powerful garrison, till 1196, when Donald McCarthy besieged and destroyed it by fire, burying the garrison in its ruins, and putting to death all who escaped from the flames, The castle was afterwards rebuilt and became a very important fortress, commanding the pass between Cork and Youghal, and was strongly fortified and garrisoned by the English. In 1575, this castle, then called the castle of Ballymartyr, was garrisoned by Fitzgerald, seneschal of Imokilly, but was attacked by the Lord-Deputy Sidney and his forces, aided by 200 of the citizens of Cork, who, after a protracted and vigorous defence, compelled the garrison to surrender, and Fitzgerald narrowly escaped by flight. In 1645 it was besieged by Lord Inchiquin, to whom it was given up on honourable terms; and during the whole period of the parliamentary war, the town was the scene of violence and depredation, and was frequently plundered and partially destroyed. In 1688 it was plundered by Lieut.-Gen. McCarthy and the Irish forces, on their retreat from Cork; and in 1690, after the battle of the Boyne and the surrender of Youghal, a detachment of 36 dragoons and 42 infantry of King William's forces charged a body of 300 Irish at this place; the cavalry pursued them to the castle, in which they took refuge, and being joined by the infantry, they compelled the fortress to surrender, and the garrison to march out without either horses or arms: in this skirmish the Irish lost 60 men killed and 16 prisoners. In 1691, after the surrender of Limerick, the Irish under Gen. McCarthy obtained possession of the town by stratagem, but were shortly after driven out by a party of the garrison from Youghal, since which time the castle has been in ruins.

The town consists of one wide street, at one end of which is the demesne of the Earl of Shannon, and at the other a bridge, beyond which a cross road leads on the right to the villages on the sea coast, and on the left to Imogeely, Fermoy, and Tallow. On the right side of this cross road, which is lined with fine ash trees, some neat houses have been recently built, forming a suburb to the town. The total number of houses is 129, most of which are large and well built, and the whole being whitewashed gives the town a very cheerful appearance. The approach from Midleton is by a magnificent avenue of lofty elms, one mile in length, and terminating at the eastern gate of Lord Shannon's demesne. About two miles from the town are Ballynona flour-mills, the property of Mr. W. Jackson, who has a neat cottage residence adjoining; the mills are propelled by a mountain stream, and produce about 12,000 bags of flour annually. Fairs are held on the 2nd of May and October; a constabulary police force is stationed here; and petty sessions are held every alternate Wednesday.

The inhabitants were incorporated by charter of Chas. II., dated July 28th, 1675, granted to Roger, Earl of Orrery, by which the castle and lands forming his estate were erected into a lordship, called the manor of Castlemartyr, with courts leet and baron, and a court of record with jurisdiction extending to £200, under a seneschal to be appointed by his lordship. The charter also granted that the castle, town, and lands of "Ballymartyr," part of the said manor, should be a free borough, under the designation of the "Borough and Town of Castlemartyr," and should extend into the county of Cork in every direction from the centre of the town, so as to comprise in the whole an area of 100 acres. The corporation was styled "The Portreeve, Bailiffs, and Burgesses," and consisted of a portreeve, two bailiffs, and twelve burgesses, who had power to admit freemen at their discretion, and to send two members to the Irish parliament; the former privilege was never exercised, nor have the limits of the borough been defined. The portreeve and bailiffs are annually elected on the Monday after St. John's day; and the burgesses, as vacancies occur, are chosen by the corporation. The portreeve has power to appoint a deputy; both are justices of the peace and coroners for the borough, during their year of office, and the portreeve for one year after. The corporation continued to return two members to the Irish parliament till the Union, when the borough was disfranchised, and the £15,000 awarded as compensation was paid to Richard, Earl of Shannon. The charter gave power to appoint a recorder and town-clerk, who were never appointed, and the only officer elected is a serjeant-at-mace, who also acts as a peace officer. A manorial court is held on the second Monday in every month, or oftener if required, by the seneschal, in which debts under £2 late currency are recoverable. The charter granted two weekly markets, but none are held; a market-house was erected in 1757, by the Hon. Henry Boyle, and a beam and scales are kept in it by the serjeant-at-mace, who receives small fees for weighing grain and other articles. There is a small bridewell belonging,to the borough, chiefly used for the temporary confinement of disorderly persons. The parish church of Ballyoughtera is situated on a gentle eminence on the north side of the town; the Ecclesiastical Commissioners have lately granted £225 for its repair. A dispensary has been established, and a fever hospital is entirely supported by the Earl of Shannon. Twelve almshouses were built for six aged men and six aged women of the borough, under a provision of the charter, authorising the lord of the manor to endow them with such lands as he might think proper. These almshouses are not kept up, and the Earl of Shannon, in lieu of them, allows £5 per annum each to 12 aged persons of the borough.

Immediately adjoining the town is Castlemartyr, the seat of the Earl of Shannon, a spacious mansion erected by the Rt. Hon. Henry Boyle, Speaker of the Irish House of Commons. It is a substantial structure, consisting of a centre with a handsome portico and two extensive wings, and is situated in a demesne of 1000 acres tastefully laid out in lawns and shrubberies, embellished with woods of stately growth, diversified with some beautiful sheets of water, and intersected with numerous walks and rides commanding fine views of the richly varied and highly picturesque scenery with which the demesne abounds. Near the house is a large and beautiful lake, and there are two of smaller dimensions within the grounds; also two canals, over one of which is an elegant bridge. The shrubberies are exceedingly luxuriant, and the flower garden contains a great number of rare and hardy exotics, which, from the mildness of the climate, attain an extraordinary size. The ruins of the old castle of Imokilly, or Castlemartyr, the ancient seat of the Fitzgeralds, mantled with ivy to the very summit, and surrounded at the base with trees of stately growth, form a strikingly interesting feature in the landscape; and within the demesne are also the ruins of the ancient parish churches of Ballyoughtera and Cahirultan. The deer park is about two miles distant; it contains some of the finest timber in the country. In the neighbourhood are numerous other seats, among which are Dromadda, the residence of G. W. Courtenay, Esq.; Kilbree, of S. W. Adams, Esq.; Kilmountain, of J. Boles, Esq.; Carew's Wood, of the Rev. J. Leslie; Ballyhickaday, of Capt. Leach; Springfield, of the Rev. W. Boles; and Castletown, of Norman Uniacke, Esq. The ruins of the ancient castle shew it to have been a place of great strength, and from the variety of its architecture it appears to have been built at different times. Richard Alfred Millikin, a gentleman distinguished for his talents and benevolence, author of a poem called "The River side" and other productions, including the well-known song of the "Groves of Blarney," was born here in 1767. The Earl of Shannon enjoys the inferior title of Baron Boyle of Castlemartyr, in the peerage of Ireland.