Graydon, George (c.1753–1803), cleric, geologist, and social reformer, was probably born at Killashee, Co. Kildare, one of four sons and a daughter of George Graydon, gentleman, and Jane Graydon (neé Maxwell). The eldest son, Robert (c.1744–1800), represented Harristown, Co. Kildare (1768–76) and the borough of Kildare (1790–97) in the Irish house of commons. George was orphaned at an early age, and educated at TCD, graduating BA in 1774 and LLB in 1782. In 1783 he was ordained a minister of the Church of Ireland, and later served as prebend in two churches associated with Christ Church cathedral, Dublin: St Michael and All Angels, High St. (1791–7), and St John's, Fishamble St. (1797–1803). He also concurrently served (1793–1803) during summer months as vicar of Burrishoole in the diocese of Tuam, and was elected third canon of St Brigid's cathedral, Kildare, in 1802.
He was elected the 100th member of the RIA in February 1786, was a member of council and secretary for foreign correspondence for much of the period between 1790 and 1803, and designed its museum of antiquities and natural history. In 1791 he travelled to Italy, where he visited the active volcanic region around Vesuvius and the area of extinct volcanoes in the north-east of the country. On this excursion he collected and purchased a large and important suite of geological specimens, many of which he arranged in the museum of the RIA on his return; these were given to the Dublin Society in 1801 and a second set lodged in TCD after his death. All are now lost except his fossil fish, which are in the National Museum of Ireland, and a few rock and mineral specimens, now in TCD and in London. He kept a catalogue of his collection, and a diary of his Italian travels, copies of which are in TCD, and published two papers in the Transactions of the RIA on fossil fish from northern Italy and on igneous phenomena near Vesuvius. He married (16 May 1795), at Newmarket, Co. Cork, Elizabeth Knott of Dublin; it is unknown if they had children.
Graydon and his wife were social reformers and concerned for the welfare of the tenants in his parish around Burrishoole. They established a straw bonnet manufactory in 1797, which provided employment and a moderate income for 200 children, and resulted in a general improvement in living standards. Later similar enterprises were set up in Co. Mayo by persons first taught by the Graydons. The bonnets were sold at Newport and further afield. Graydon reported on this work in a memoir published by the Dublin Society in 1802, and it rewarded his wife with a premium of twenty-five guineas (£26.25) and a gold medal. He was an honorary member of the Dublin Society. He died in 1803, probably in Dublin, and in considerable debt, having earlier taken on responsibility for his brother Robert's financial affairs. His widow married (3 April 1806) William Smyth of Drumcree, near Mullingar, Co. Westmeath.