Archer, James (c.1632–c.1680), military engineer and architect, was born in Kilkenny. His early life remains obscure, but he was a royalist, left Ireland at some point, and entered the French service; he later claimed to have served six years as a lieutenant, and twenty-four years as an ensign, gaining considerable experience as a military engineer. His family owned estates in Co. Kilkenny and Co. Wexford, but these were confiscated in the 1650s. He returned to England after the restoration of the monarchy; his movements during the 1660s are largely obscure, though he seems to have been employed in France and the Netherlands by Lord Arlington, the secretary of state, to gather intelligence on the possibility of French intervention in Ireland. In October 1665 his assistance was requested by Archbishop Hugh O'Reilly (qv) who was seeking permission to return to Ireland. In England again (c.1665–6), Charles II apparently promised to look after his welfare. Archer later claimed that his service abroad had precluded him from lodging any case with the court of claims (1662–3). This period of his life was marked by penury, and he would suffer financial difficulties for the remainder of his life. During this period (1666–70) Archer may have been employed by Arlington to carry out work on his country house in Suffolk, Euston Hall.
A client of James Butler (qv), duke of Ormond, on 26 November 1667 Archer reported to Ormond on the possibility of opening Carrick-on-Suir to maritime trade. Ormond was intent on the town's development, and Archer's report was favourable; in November 1668 he was employed in the construction of a bridge at Carrick-on-Suir and in clearing the river to facilitate maritime traffic, though he rejected an offer of £3 payment for this. He also carried out repairs to Ormond's residence in Carrick. In December 1668 he warned Ormond that copies of the Narrative of the earl of Clarendon's settlement and sale of Ireland (1668), by Nicholas French (qv), were being circulated, ‘wherein it is set forth publicly amongst that factious people that your grace is the only man that destroyed the Irish nation’ (Ormond MSS, new ser., iv, 289). In early 1669 he was probably employed to work on both Ormond's residence in Clonmel, and Kilkenny castle; this remains uncertain. On 22 August 1669 he was recommended for a pension of £100 by the then viceroy, John, Baron Robartes (qv). In 1669 he was employed in a survey of Guernsey in the capacity of royal engineer, but was never paid the £150 due for this. In February 1671 he was asked by Ormond to report on the condition of Irish fortifications; he also instructed Thomas Butler (qv), Lord Ossory, on fortifications to enable Ossory to inspect them personally. At some point (April 1672 × September 1674) Archer petitioned Arlington and the king for payment of his pension, or to provide letters of recommendation to enable him to make a new life abroad. In February 1673 he was sent on a mission to Guernsey to inspect damage caused by lightning: ‘the like was not seen since the creation’ (CSPD 1672–3, 459).
On 26 January 1678 Ormond recommended Archer to Roger Boyle (qv), earl of Orrery, to work on Rincurran Fort (later Charles Fort) in Kinsale. Of the two available engineers, Archer and William Robinson (qv), Archer was considered the more experienced, and, unlike Robinson, was in a position to remain on site to oversee the construction. The contracts for the fort were signed on 12 March 1678 and Robinson was ordered to return to Dublin, leaving Archer in charge. His position was difficult as he was subordinate to both Robinson and Orrery, though he was expressly ordered to obey the latter. By August 1678 Ormond intervened in a dispute between the three; it was decided that the final design of the fort would be Robinson's rather than Archer's. Orrery assisted Archer in maintaining discipline on the site, and by December 1678, having formed a high opinion of Archer despite his catholicism, had recommended that both he and his staff be permitted to carry arms.
Archer died c.1680. On 17 January 1681 his widow, Anne, was granted £350 in arrears due to Archer from the ordnance office. The details of the family are obscure, but Archer had five children. Three sons, Francis, James, and Walter, all became engineers; the eldest, Francis, was killed in the Dutch service at the siege of Maastricht in 1676.