Dawson, Joshua (1660?–1725), government official and property developer, was born c.1660, the third of four sons of Thomas Dawson (1630?–1683), deputy commissary of musters of the army, who in 1657 purchased from the heirs of Sir Thomas Phillips (qv) the eight townlands of Moyola, Co. Londonderry, and in 1673 a lease from the Drapers’ Company of the manor of Moneymore in the same county. It was probably this Dawson who built a bridge over the Moyola, the largest single-span stone bridge in Ireland, the place becoming known after his death as Dawson's Bridge. Thomas Dawson's grandfather, Christopher Dawson, a native of Westmorland, had settled at Drogheda, Co. Louth (1611). Thomas's eldest son, also Thomas (1653–1732), was MP for Antrim borough (1695–9).
Joshua Dawson was appointed to the junior of two clerkships in the chief secretary's office in Dublin in 1690, the senior clerk being his maternal uncle, Arthur Podmore, who had been in office at Dublin Castle since c.1667. After Podmore's death (1697) Dawson succeeded as chief clerk or under-secretary, holding this office until he was removed by Chief Secretary Joseph Addison (qv) in October 1714. He was ‘an early example of a professional civil servant’ (HIP). Dawson was MP for Wicklow borough from 1705 to 1714. Though a tory, he was no friend of the catholics; he commented on a proclamation against unregistered and non-juring priests (1712) that the laws should be enforced against ‘those vermin that are always contriving the destruction of our constitution’ (HIP). He held three lucrative offices: clerk of the paper office (1703–25), comptroller of customs for Drogheda (1703–8), and customer of Dublin (1703–15).
As early as 1695 Dawson received, jointly with Podmore, a grant of lands in Co. Waterford. In 1705 he acquired 8 acres of land between Trinity College and St Stephen's Green and began laying out streets on a grid pattern: Dawson Street (in which in 1706 he built a fine house for himself), Duke Street, and Anne Street (both linking Dawson Street with Grafton Street, the east side of which was the limit of his property). By a private act of parliament (1705) and a conveyance (1708) he acquired the Moyola and Moneymore estates from his brother Thomas. In 1710 he obtained a patent to erect the Moyola estate into a manor by the name of Castle Dawson; by cheap land grants he encouraged many protestant families to settle. His activities as a property developer continued after he lost political influence with the death of Queen Anne. In 1715 he sold his Dublin house (for an asking price of £3,500) to Dublin corporation as a residence for the lord mayor – the Mansion House.
Joshua Dawson died 13 March 1725. He married (January 1696) Anne, elder daughter of Thomas Carr of Donore, Co. Kildare, and with her had fourteen children, of whom at least four sons and three daughters survived to adulthood. The eldest son, Arthur (1698–75), became owner of Castledawson; he was MP for Co. Londonderry (1729–42) and baron of the exchequer (1742–68). The second daughter, Mary (d. 1770), was mother of Sackville Hamilton (qv). There are portraits of Joshua Dawson, his wife Anne, and other close relatives at Castledawson.