Named as a beneficiary in his father's Will (written 1833).
In 1841 John Tremayne (45), copper assayer, and wife Maria Tremayne (39) were living in Croillas? Ludgvan. With them were children: Phillipa (10), John (4), Susan (1).
In 1851 Jno Tremayne (53) of Phillack, copper assayer, and wife Maria Tremayne (49) of Camborne were living in Pendarrick? Camborne. At home were children: Phillippa (20) of Gwinear, Jno (14) of Phillack.
In 1861 John Tremayne (64) of Phillack, widower, assayer, was lodging with [his daughter] Philippa and her husband John Jenkin in Camborne. With him was son John (24) of Gwinear, miner.
In 1871 John Tremayne (76) of Phillack, widower, copper ore assayer, was lodging in Camborne, Cornwall.
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TREMAYNE—At Tuckingmill, March 31, Mr. John Tremayne, late of Angarrack, Hayle, aged 81.
Royal Cornwall Gazette, 13 April 1877, p. 8