MARGARET'S-ST, a parish, in the barony of COOLOCK, county of DUBLIN, and province of LEINSTER, 5¾ miles (N.) from Dublin, on the old road to Naul, and about a mile from the mail coach road from Dublin to Ashbourne; containing 335 inhabitants, of which number, 96 are in the village. A fair is held on July 30th and 31st for the sale of horses and cattle. The principal seats are Dunbroe House, the residence of Miss Giles; Newtown, of Mrs. Stock; Newtown House, of B. Shew, Esq.; Harristown House, of P. Brennan, Esq.; Harristown, of J. Moore, Esq.; Kingstown House, of J. Shew, Esq.; and Barberstown House, of M. Brangan, Esq. In ecclesiastical arrangements it is a chapelry, in the diocese of Dublin, forming part of the benefice of Finglas and the corps of the chancellorship of St. Patrick's, Dublin: the composition for tithes is included in the amount for Finglas. The church is in ruins. Over the door of a small adjoining chapel is a Latin inscription purporting that it was built by Sir John Plunkett, formerly chief justice of the king's bench in Ireland. In the R. C. divisions the parish also forms part of the union or district of Finglas and has a neat chapel in the village, in which is also a national school. About a mile distant are the ruins of Dunsoghly castle, consisting of a tower, still roofed, and the remains of a large hall, or diningroom, and kitchens: the tower is vaulted at the bottom, and it had three stories; the floors of the two upper stories have fallen in, but the room of the principal floor is in tolerable repair: the view from the top is very extensive. The ancient family of Plunkett originally owned this property, which now belongs to Mrs. Cavenagh, who inherits it through her grandfather. Adjoining the ruins are the remains of a private chapel, over the doorway of which is a tablet of freestone, exhibiting the emblems of the crucifixion, in high relief, with the letters and date i. P. M. o. 6. s. 1573, at the bottom. Mr. B. Shew, on planting an elevated spot in his grounds, a few years since, discovered a great quantity of human bones, supposed to be some of those who fell in the various skirmishes which at different periods have taken place in this district. Near the chapel is a tepid well, or bath, dedicated to St. Bridget, said to contain lime, muriate of soda, nitrate of kali and sulphur, but the last in only a small proportion.