Knocknagin House, Its out buildings and various ruined dwellings to the west and north of the property, sits in the downland of Knocknagin, just south of the border between North Fingal and County Meath. The River Delvin forms this border.

    Knocknagin House is a 2 story 3 bay central block with attic floor lit by a pedimented attic window, with a wing attached to each gable. The house was built around 1680. The casement windows with panes and shutters are a more recent replacement, circa 1860. The roof is gabled with a chimney stack on each gable. The wings are single story and with the house form the east boundary to a rear-enclosed yard. This yard is also bounded by single story lofted buildings that would appear to have been thatched at one time. This thatch is reported to have blown off during the night of the “Big Wind” on the 6th and 7th of January,1839.

    Even though the original house dates from the late 17th Century, there have been considerable alterations throughout the years. The suggested building date of 1680 is based on descriptions in Brian de Breffini and Rosemary Ffolliotts ‘The Houses of Ireland’ which states that: “About 1680 one type of stone house became increasingly favored in Munster and Leinster. This was a two-story, single-pile with garrets, a stair in the return at the centre back and external chimneys with panelled stacks on the gable-ends. The layout is illustrated by the floor-plan of Moyvaine, Co. Limerick, The Moyvanine banisters are identical to those at Castle Salem, and the two houses were undoubtedly built about the same time, 1682. (An almost identical house stands on the downland of Sheephouse in the parish of Donore, Co. Meath), Mount Odell (formerly Kilcrump), Co. Waterford, is a variant of this type; its floor plan is the same as Moyvainine’s, but its height is considerably greater, having an additional story. It was built by Charles Odell in 1678.”

    Behind Knocknagin House there exists the remains of the village of “Knocknagin,” which consisted of dwelling Houses, a bakery and an ancient “street” that linked up with the Dublin/Drogheda stage-coach road to the west. A series of underground stone culverts can also be seen around the house, and these extend beyond the “street” to the orchard and fields beyond, Additionally, at the far western end there are the remains of an old mill, once fed by man made irrigation channels carrying water diverted from the Delvin River, Clearly, the main activity on the lands of Knocknagin at this period would seem to have been intensive fruit farming, taking advantage of the “micro-climate” in the Delvin River Valley.

    Knocknagin, the place name, is derived from the Irish, Cnoc ma Cean, a burial mound at the estuary of the Delvin River. The spelling of the place name has altered over the centuries from Knockengen to Knockingen for example, to its present form Knocknagin. 

    Knocknagin (Cnoc na Cean) is mentioned be the ancient annalists, and appears to have its origins in a battlw at the moth of the River Delvin, where thousands of invaders were slain and buried. Dr Hanmer in his ‘Chronicle of Ireland’ reports that “the second company of the ‘invading’combination came to Lambay, landed their men at the “Follesse of Skerries,” set them in battle array, and marched to a place now called Croc na cean, (hill of the heads).” It was there that Dermott Lamhdearg, King of Leinster, met them. They fought a cruel battle with equal fortune for the space of four days, when finally the strangers were overthrown, and 36,000 of them slain and buried in a mound at this spot.

    This burial mound was excavated by George Hamilton of Hampton during the building of the Dublin to Drogheda railway, and he wrote about it as follows: “I had it opened, and found it composed of small round stones with shingle from the sea shore, The excavations were soon interrupted by a circle of high stones, which appear to have been placed around, but at some distance from the centre of the mound, and quite covered with, or buried in shingle. Within this outer circle I found a crude platform, of apparently beaten clay, and upon this an immense heap of burned human bones. As far as could be surmised, the bones were those of human beings of every age. In the center of this circle was discovered a chamber, constructed of huge flags, some of them more than six feet in height, and within this crude stone basin, or rather a large stone of sandstone grit, not found in the neighbourhood, with a cavity or hollow formed in it. This stone bore evident marks of fire, and around it on all sides were remains of charcoal, or burned wood, and a quantity of semi-calcined human bones. Amongst these bones were scattered a number of beads, formed of polished stone, or a conical shape, with a hole through each, near the apex of the cone, the mass of bones was very large. The stones have, I fear, been used in the railway, but the remains of the chamber and two or three of the flags may still be seen in the face of the cliff, I may add, that a few years previously, Mr. Shaw, of Delvin Lodge, in cutting a ditch across one of his fields on the lands of Knockingen, came upon a considerable number of skeletons: and in my own immediate neighbourhood, on the lands of Balbriggan, rude stone coffins, with human skeletons, are found very frequently. Several were discovered during the last year in one of the fields belonging to Mr. Matthews, of Tannerstown.”

    the earliest reference to ownership of the lands of Knocknagin are in The Civil Survey 1654-1656. It refers to a George Stokes and a Thomas Conrad as owning land at Knockengen. the Conran family were wealthy, landed gentry, involved in mercantile activity with England whose country seat was at “Curragh” in the Barony of Balrothery on the Meath border, these Conrad’s were also Aldermen of Dublin. 

    Following the Battle of the Boyne in 1690, late tracts of land and estates were confiscated by the Crown. It is hard to know exactly what happened to Knockengin during this time, but we do know that on the 27th October, 1721 Robert Echlin of Rush, County Dublin, landowner and agent of the Duke of York, sold 158 acres at Knockengen from the Duke’s estate to one Henry Martin. He lived at Knockengen until his death 1733, when Knockengen was left to his widow Mary and sons James and Thomas. 

    James Martin, eldest son of Henry, later sold some land to George Lowther of Co. Meath in 1799, and it is probable that the now demolished house of Lowtherstone on the nearby coast dates from this time. 

    It would appear that during this period of ownership by the Martins (18th Century) that substantial works were carried out at Knocknagin, The high walls enclosing the orchards on the property were built to provide shelter from the north and east winds, and the ground area was divided up using regular shill covered paths. During this period also, a large 3-storey staircase block was added to the rear of the house, probably replacing an earlier 2-storey staircase. The staircase has survived in perfect condition with only the treads and rises of the first flight needing replacement in 1995.

    We find that Knockengen in 1827 was now owned by the King family, but wether this was through the Martins selling the lands, or by marriage is not known. On December 9th of that year James and Margaret King of Knockengen sold 85 acres of land to William O’Reilly (1792-1844) of Knock Abbey, Co. Louth, Another parcel of the lands surrounding Lowther Lodge was sold in 1816 by the Kings to one Townley Filgate. 

    The O’Reillys were prominent Catholic landed gentry. During their tenure, it appears that Knocknagin underwent many more substantial alterations. The stone gate piers around the property were built during this period, and one can assume from the positioning of these that the street at the rear had ceased to be a public thoroughfare. Furthermore, it is likely that the orchards were no longer the main source of income at Knocknagin.

    The O’Reillys had other means, and Knocknagin became simply a pleasurable residence, with the surrounding lands rented out to farmers.

Knocknagin House was altered around this time to suit the lifestyle and social standing of the O’Reillys. The wings to each side of the central block of the house were adapted from lofted outhouses to become a large drawing room or ballroom to the west, and a further two living rooms complete with lofted servant quarters to the east. The French windows on the front facade also date from this period, replacing Georgian sash windows, and with the granite window sills clearly added to rather than replaced.

    It is interesting to note that the Building of the Catholic Church of St. Peter and Paul in Balbriggan commenced in 1838, following the Catholic Emancipation of 1829. In the records of a Parish minute book there is an note of monies raised from two balls held at Knocknagin. 

    Myles William Patrick O’Reilly (1825-1880) only son of the aforementioned William continued to live at Knocknagin until his death in 1880. He was a soldier and later a prominent Catholic politician. He joined the Louth Rifles Militia, and in 1860 entered the service of the Pope where he was appointed to the command of the Irish Brigade. In September 1860 the Battalion of St. Patrick defended Spoleto against the Piedmontese troops, and O’Reilly was decorated by the Pope for his efforts. 

    After his return to Ireland he was elected M.P. for the country of Longford in March 1862, and for many years he occupied a prominent place in the House of Commons among the debaters on Irish and military subjects. He was a member of the home-rule party, and was loyal to the leadership of Isaac Butt. He was a magistrate for the counties of Louth and Dublin.

     It is from the 1868 ordinance survey (Parish) carried out by Lieut. Engledue RE. That an idea of the early layout of the gardens can be seen. The planting of which survives from this period is typically Victorian, and include Irish yew, weeping ash, araucaria, philadelphus and laurel. In view of the substantial alterations made to the house by the O’Reilly’s, we assume that these gardens around the house were also laid out by the O’Reillys, and that this was a more formal manner than they had heretofore been.

    During the period from Major O’Reilly’s death in 1880 to 1891, we learn from advertisements in Dublin newspapers of the time that Knocknagin was available to rent “with all modern conveniences.”

    In 1891 Knocknagin was sold to Michael Wade of Balbriggan. Michael Wade and two of his four sons after him, lived and farmed the lands at Knocknagin until 1991when the last surviving son John died. Sometime after that, the ownership of the house passed to the current owners.