Colley (Cowley), Sir George (d. 1614), landowner, was the son of Sir Henry Colley of Edenderry, King's Co. (Offaly), first governor of Philipstown, seneschal of King's Co., and member of the Irish council. The family had come to Ireland in the 1530s when Robert Cowley (qv) had held the office of master of the rolls in Ireland and later of commissioner for the Leix–Offaly plantation; his son Walter was a surveyor for the plantation and the family were subsequently granted land there. George inherited his father's estate of Castle Carbery, Co. Kildare, and in 1579 was appointed seneschal of Carbery for life. He also acquired the lease to the site and possessions of the monastery of White Friars of Kilcormock in O'Molloy's country, King's Co., stated to be in consideration of his father's service. In 1583 Colley sued for a pardon for himself and several Englishmen from the barony of Carbery, and the following year sued again for a pardon for himself and others, this time mostly of Gaelic origin, from Edenderry, King's Co. The pardon was granted in February 1584; it is not stated what this was for, but breaches of the law frequently occurred at this time as the plantation stagnated after the rebellion of the O'Mores and the O'Connors. Colley, along with one or two other prominent landowners, took advantage of the scarcity of new settlers at this time and greatly enlarged the family holdings in Offaly – a feature of the Leix–Offaly plantation that alarmed Elizabeth and her government. In May 1597 Colley, his wife Margaret, and his feofees were fined £5 and again granted a pardon, this time for intrusions and alienations for the lands of Edenderry. Colley, however, continued to be an important agent of the government. In 1588 he was appointed to a commission to take the musters and array of the inhabitants of Offaly, and was knighted in 1593. A new round of attacks began in 1596 in Leix–Offaly, led by Uaithne O'More (qv), and at Edenderry Colley had his cattle driven off and his country harried to the very doors of his castle. In 1598 the escalation of the war led to Colley being appointed to a commission to execute martial law in King's Co.
Colley married Margaret, daughter of the lord chancellor, Adam Loftus (qv). His brother Henry also married a daughter of Loftus. In 1579 Loftus procured for his son-in-law George a promise of the advowson of the archdeaconry of Dublin on the next vacancy, and the following year pleaded for the continuation of his pension. Sir George Colley died 17 January 1614 and his estates were taken over by Sir William, his son and heir. He had two other sons (Adam, who died young, and Robert, who died unmarried) and a daughter, Margaret. William Colley represented Edenderry in the 1613 parliament and again in the parliaments of 1634 and 1640, and in 1643–4 was sheriff of the county; he was knighted in 1615. George Colley's widow, Margaret, later married Edward Blayney.