Beresford, Tristram (1574–1647/9), planter, was third of seven sons of Michael Beresford and Rose Beresford (née Kevitt) of Kent, who also had four daughters. John Clotworthy (qv) was a relation. In 1610 Beresford was sent by the Honourable the Irish Society of London to oversee the building and fortification of the town of Coleraine, Co. Londonderry, and in the town's first charter (25 March 1613) Beresford is named as portreeve; he was later the first mayor. He laid the foundations of his family's wealth by acquiring large estates and by profiting from the timber resources of the area. A survey for the London companies (1613) noted that he had used his position for personal gain; he was found guilty of corruption. However, as blame for abuses fell chiefly on his superior, John Rowley (qv) (d. 1617), Beresford managed to retain the Londoners’ confidence, and in 1616 was agent for the Irish Society. The London companies were continually criticised, especially by Beresford's lifelong enemy Sir Thomas Phillips (qv), for failure to carry out their undertakings. In 1625 the privy council in London demanded the Society's rents, but Beresford managed to collect and remit them before the sequestrators arrived. Beresford sat as county member for Londonderry in the 1634 parliament. In 1635, during Star Chamber proceedings against the Irish Society, Phillips alleged that Beresford's tyranny in Coleraine equalled that of the Spanish inquisition. Beresford's lands, like the London companies’, were declared forfeit to the crown, but in 1641 parliament voted to restore them. He survived the rebellion of 1641, dying in Coleraine in 1647 or 1649. By his marriage to Susanna Brooke of London, there were three daughters and three sons: Tristram (below), created a baronet; Sir Randal, an unpopular mayor of Coleraine; and Michael (d. 1660), commissioner for the civil survey and revenue. One of his daughters married Sir Edward Dodington (qv), and another married first William Jackson of Coleraine and secondly John Mitchelburne (qv).
Beresford's eldest son, Sir Tristram Beresford (d. 1673/5), may have been born in Coleraine, where his father acquired large estates. He was governor of the castle of Culmore until removed after a Star Chamber ruling of 12 May 1635; was MP for Counties Londonderry, Donegal, and Tyrone (1656–8) in the protectorate parliament; represented Londonderry in the general convention in Dublin (1660); and sat for Londonderry (1661–6) in Charles II's Irish parliament. He was created a baronet (5 May 1665) and died 15 January 1673 or 1675. He married first Anne, daughter of John Rowley of Castleroe; they had a son, (Sir) Randal, and two daughters. He married secondly Sarah Sackville; they had four sons and three daughters.