Of Heath House, Queen's County
From Irish Pedigrees; or the Origin and Stem of the Irish Nation by John O'Hart
Arms: Same as "O'Reilly" (No. 2).
MYLES, surnamed "The Slasher," a younger brother of Terence (or Tirlogh), who is No. 124 on the "O'Reilly" (No. 2) pedigree, was the ancestor of this branch of that family.
124. Myles O'Reilly, "The Slasher:" son of Edmond, of Kilnacrott, who was the last "Prince of Brefney."
125. Colonel John Reilly: son of Myles: omitted the prefix O'; raised at his own expense for the service of King James II., a regiment called "Reilly's Dragoons," at the head of which he fought at Derry, Belturbet, the Boyne, Aughrim, and Limerick, but saved his property from confiscation by being included in the Articles of the Treaty of Limerick. He married Margaret, dau. of Owen O'Reilly, Esq., by whom he had five sons and two daus., some of whom d. without issue. He died on the 17th Feb., 1717, and was buried in the old churchyard of Kill, parish of Crossarlough, county Cavan, where, in 1836, his tomb was in good preservation. His surviving children were:
I. Connor, who was a Captain in his father's regiment, d. s. p.
II. Myles, who was a linen-draper in Dublin, had three sons who all d. s. p.
III. Bryan, also a Captain in his father's regiment, and of whom presently.
IV. Thomas, who was a Lieut. in his father's regiment, mar. and had four sons and an only daughter: 1. Patrick, d. s. p.; 2. Philip, a Priest; 3. James; 4. Count Alexander O'Reilly, of Spain, born 1722 (see Note "O'Reilly," under O'Reilly, No. 1 pedigree, p. 743).
126. Bryan O'Reilly: third son of Colonel John Reilly; had six sons, all of whom except the eldest d. s. p.
127. Myles: the eldest son of Bryan; had three sons:
I. Dowell, of whom presently.
II. John Alexander O'Reilly, a Colonel in the Spanish Service, d. s. p.
III. Matthew, who had seven sons:
1. Matthew, who d. s. p.
2. John, who d. s. p.
3. Myles, who d. s. p.
4. William, who was father of the late William Patrick O'Reilly, Major in the Pope's Brigade, and Assistant Commissioner of the Board of Intermediate Education in Ireland.
5. Walter, who d. s. p.
6. Dowell, of Jamaica.
128. Dowell O'Reilly: eldest son of Myles; was the first of the family that conformed to the late Established Church in Ireland.
129. Myles John O'Reilly, of Heath House, Queen's County: son of Dowell.
130. Myles George O'Reilly: son of Myles John; representative of Colonel John Reilly; living in 1861.
 Daughter: This only daughter of Thomas O'Reilly, the fourth son of Colonel John Reilly, married a Captain Adams, who assumed the name O'Reilly; from that marriage the "O'Reillys" of Belmont are descended.
 James: This James O'Reilly had two sons: 1. Thomas, and 2. Anthony, who d.s.p. This Thomas had six sons: I. James, of whom presently; II. Robert; III. Thomas; IV. Anthony; V. Stephen; VI. John. And this (I) James had: 1. James, who d. s.p.; 2. Thomas, who d. s.p.; 4. Anthony, who had James W. Fortescue O'Reilly, the representative of the line of Thomas O'Reilly, the fourth son of Colonel John Reilly, son of Myles O'Reilly, "The Slasher."
 Spain: For the descent of this Count Alexander O'Reilly of Spain, see Burke's Landed Gentry.