Barnewall, Sir Richard (1602–79), politician, was eldest son of Sir Patrick Barnewall of Crickstown, Co. Meath and his wife Cicely, daughter of William Fleming, Lord Slane. Sir Patrick, head of a minor though long-established branch of the Barnewall family, died in 1624, and Cicely married his namesake – another prominent member of the Pale gentry – Patrick Barnewall (qv) of Kilbrew. In 1621 Richard married Thomasina, daughter of Edward Dowdall of Athlumney, Co. Meath, who died shortly after the birth of their only child, Mary. His second wife was Julia, daughter of Sir Gerald Aylmer of Dunadea, Co. Kildare, with whom he had six sons and five daughters.
Elected to the 1640 parliament for Co. Meath, Barnewall helped draft the articles of impeachment against leading members of the Dublin administration. Along with a number of catholic MPs, he attempted to initiate dialogue with the insurgents after the outbreak of the Ulster rebellion in October 1641. Frustrated in these efforts by the hard-line policy of the lords justices, Barnewall attended meetings at the Hill of Crofty and Tara, helping to forge an alliance between the Ulster rebels and the Pale nobility. Appointed to a council of war to assist Nicholas Preston (qv), 6th Viscount Gormanston, he was also responsible for raising troops in the baronies of Ratoath and Dunboyne. Officially expelled from the Irish parliament on 22 June 1642, and outlawed in November 1642, Barnewall played a prominent role in the establishment of the confederate association. He moved to Kilkenny, and attended the first general assembly there (October). The assembly appointed him as muster-master general of the Leinster army, as well as a member of the Leinster provincial council. After the death of Gormanston in July 1643, Barnewall replaced him on the committee negotiating a truce with James Butler (qv), 12th earl of Ormond. The two sides signed a cessation agreement (September), and for the next five years Barnewall enthusiastically endorsed the idea of a permanent peace treaty with the royalists. Apart from his political activities, he maintained close links with the Leinster army, led by Thomas Preston (qv).
Disillusioned by events in late 1646, when the clerical faction succeeded in overturning the first Ormond peace treaty, Barnewall approached the royalists directly in April 1647, claiming to speak on behalf of the Meath gentry. He subsequently became involved in plots aimed at subverting confederate government, while at the same time continuing to serve with the Leinster army as governor of Monasterevin. Events at the general assembly in December 1647 marked the recovery of the peace faction in Kilkenny. Barnewall was elected to the executive supreme council, opposing the clerical faction in the civil war that erupted during 1648. He attended the final general assembly (September), where he assisted in negotiating a revised settlement with Ormond. By the terms of the peace treaty signed in January 1649, Barnewall served as one of twelve commissioners of trust, nominated to rule in association with the lord lieutenant.
During the summer of 1649 Ormond sent Barnewall and Sir Luke Fitzgerald on an ultimately successful mission to treat with the general of the Ulster Irish, Owen Roe O'Neill (qv), who had opposed the peace settlement. In 1651 the new royalist commander, Ulick Burke (qv), marquis of Clanricarde, appointed him commissioner for Leinster with full authority in both civil and military affairs. The following year he negotiated a surrender with the forces of the English parliament, which officially ended the war in the province. Barnewall forfeited his land and property, but none the less received 2,500 plantation acres in Connacht in 1656. After the restoration of Charles II, he was named in the 1662 act of settlement as meriting special favour. Along with many catholics, however, Barnewall experienced difficulties in recovering any lands, and his case required further clarification in the subsequent act of explanation. He died peacefully in July 1679. His heir Sir Patrick was MP for Co. Meath in the 1689 Jacobite parliament.