The Reverend Henry Hawkins Tremayne (1741 – 1829) was a member of a landed family in the English county of Cornwall, and owner of the Heligan estate near Mevagissey, with significant interests in the Cornish tin mining industry. He is credited as initiating the creation of the set of gardens around Heligan House that are now well known as the Lost Gardens of Heligan.
Henry Hawkins Tremayne was born in 1741, the second son of John Tremayne and Grace Hawkins. He was baptized at St Ewe on 17 July 1741, and was educated at Blundell's School in Tiverton. He attended Balliol College of the University of Oxford, where he matriculated in May 1759 and graduated as a Bachelor of Arts in 1763. Like many second sons of landed families, he was destined for a career in the Church of England, where he was ordained as a deacon in 1766. He took up the post of curate at Lostwithiel.
Henry's older brother Lewis died shortly after Henry's ordination, leaving Henry the unexpected role of heir to the Heligan estate. In 1767, he married Harriet, the daughter of John Hearle of Penryn, a former vice-warden of the stannaries. As a consequence, he inherited a third share of the extensive Hearle estates and mining industry. In 1808 a further inheritance brought him the Tremayne estates at Sydenham in Devon.