He was third son of Robert Cotes, mayor of Galway, who settled in London, became a doctor and married Elizabeth, daughter of Francis Lynn, chief secretary to the Royal African Company.
[1] Cotes retired from active life some years before his death.
He resided in Paradise Row, Chelsea, London, where he died 7 March 1818 in his eighty-fifth year.
During this time he resided at 25 Percy Street, Rathbone Place.
[1] Cotes was twice married, first to Mary Creswick in 1768, and secondly in 1780 to Sarah Shepherd, an artist, who died 27 September 1814, aged 76.