Pelham, Henry (1749–1806), miniaturist, was born in Boston, Massachusetts, son of Peter Pelham (1697–1751), mezzotint engraver, and his third wife Mary Singleton Copley. She was the widow of Richard Copley and mother of the distinguished American artist and miniaturist John Singleton Copley (1738–1815), RA. Henry Pelham attended the Boston Latin School, and later studied engineering and learned to engrave mezzotints. He worked as an assistant to John Singleton Copley, who painted Pelham's portrait in his ‘Boy with a squirrel’ (Museum of Fine Arts, Boston), painted about 1758 and exhibited in London. Copley taught him to paint miniatures during the 1760s and eventually Pelham took over Copley's successful miniature painting business in 1772. In Boston Pelham had a busy practice as a miniaturist and portrait painter in oils. During the 1770s he received many important commissions from the leaders of Massachusetts society. It was during this time that Pelham began working as a map-maker and in 1775 he made a plan of Boston which was published in aquatint in London in 1777. However, the political climate in Boston adversely affected his practice. In 1775, on a journey to Philadelphia on horseback, Pelham was attacked as a tory and a loyalist. The siege of Boston put a stop to his work and his property was destroyed. He left Boston in 1776 to join John Singleton Copley at Leicester Fields, London. There Pelham exhibited ‘The finding of Moses’ in 1777 and five miniature portraits at the Royal Academy during the years 1777–8. To supplement his income as a painter he taught perspective, geography, and astronomy.
Signed miniature portraits by Pelham painted after 1778 are rare, and most of his extant work was done in America in 1773–5. His miniature portraits are well posed, expertly drawn, and are very well painted with heightened light and shade. Pelham's characteristic brushstrokes are vigorous with cross-hatched lines that model the face. The backgrounds are usually dark and broadly painted.
Pelham had family connections with Ireland through his mother, as both Mary Singleton and her first husband Richard Copley were born in Ireland. Before he left Boston Pelham had corresponded with his uncle, John Singleton, who lived at Ballygirreen near Newmarket-on-Fergus, Co. Clare. In 1778 or 1779 Pelham settled in Ireland; he lived in Dublin and Co. Clare before moving to Co. Kerry to manage the estates of William Petty (qv) (1737–1805), later 1st marquess of Lansdowne. Pelham continued to work as a miniaturist, painting portraits of members of the O'Brien family of Dromoland Castle, Co. Clare, and a portrait of the countess of Desmond which was engraved in aquatint by Nathaniel Grogan (qv). He exhibited a frame containing seven miniature portraits at the Society of Artists’ exhibition in Dublin in 1780, when his address was given as 48 College Green. Pelham married the daughter of William Butler of Castle Crine, Sixmilebridge, Co. Clare. As well as painting miniatures, Pelham worked as an engraver and mapmaker and did topographical views. He supplied drawings of Quin abbey, Clare abbey, and Ennis abbey which were engraved for Francis Grose's The antiquities of Ireland (1791–5). Pelham surveyed Co. Clare and worked as a civil engineer. In late September 1806 he drowned in Kenmare River when his boat capsized while he was overseeing the construction of a Martello tower which he had designed.