Browne, John (1709–76), 1st earl of Altamont , landowner, and MP, was born at Mount Browne near Westport, Co. Mayo, the only son of Peter Browne (d. 1722), a catholic landowner, of Mount Browne, and his wife Mary, daughter of Denis Daly (qv) of Carrownakelly, Co. Galway, judge of the court of common pleas. While his sisters were reared as catholics, he was brought up a protestant and entered Christ Church, Oxford, in July 1725, aged 16. He was high sheriff of Co. Mayo (1731), MP for Castlebar, Co. Mayo (1744–60), and governor of the county (1752–61, 1765–75). Although initially his income was a relatively modest £700 a year, he was a man of great ambition. He rarely attended parliament, but when he did he usually supported the government, and was present to vote for the money bill of 1753. He commissioned Richard Castle (qv) to rebuild Westport House in 1731, and in 1773 decided to double its size (completed in 1782). An improving landlord, he invested heavily in his estate: Arthur Young (qv) described his efforts at land reclamation and his introduction of new crops and superior livestock; he was also a keen horse-breeder and kept a stable of racehorses. He played an important role in encouraging Westport's linen industry, building new houses for weavers, financing their purchases of looms and yarn, and buying up their surplus produce. By the 1770s there was a thriving linen trade in the town, from which Browne drew substantial profits. Raised to the Irish peerage as Baron Mount Eagle of Westport (20 August 1760), he was advanced to Viscount Westport (24 August 1768) and earl of Altamont (4 December 1771). He died at Westport House 4 July 1776. His portrait, painted by Sir Joshua Reynolds, can be seen in the long gallery of Westport House.
In 1729 he married Anne ‘Nancy’ (d. 1771), daughter of Sir Arthur Gore (1682–1742), of Newtown Gore, Co. Mayo, MP for Co. Mayo (1715–42), and sister of Arthur Gore (d. 1773), 1st earl of Arran; they had six sons and a daughter. Four of Browne's sons sat in parliament and formed a tight political unit: Peter (1731?–1780), 2nd earl of Altamont (1776–80), was MP for Co. Mayo (1761–8); Arthur (1732–79) was MP for Gowran, Co. Kilkenny (1769–76), and Co. Mayo (1776–9); George (c.1735–1782) was MP for Co. Mayo (1779–82); and James (c.1736–1790), was MP for Jamestown, Co. Leitrim (1768–76), Tuam, Co. Galway (1776–83) and Castlebar, Co. Mayo (1783–90), and prime serjeant of Ireland (1780–82, 1784–7).