Coordinates: 51°40′12″N 4°00′32″W / 51.670°N 4.009°W Penllergare is a country park in Wales. It was the estate of John Dillwyn Llewelyn adjacent to what is now the village of Penllergaer, Swansea. Although the names are similar, the village of Penllergaer grew up as a separate entity from the Penllergare estate.
At the height of its prosperity in the nineteenth and early twentieth centuries, the Penllergare estate, on the north-west fringe of Swansea, was one of the great gardens of Britain. Its main creator was John Dillwyn Llewelyn (1810–82), a man as distinguished for his contribution to landscape design and horticulture, as for his scientific experiments and pioneering photography.
Penllergare provided inspiration for the expression of Dillwyn-Llewellyn's talents. Taking in the adjacent estate of Nydfwch and based on the work of his father, Lewis Weston Dillwyn, John exploited the natural beauty of the site in his grand design to create a landscape planted with a rich variety of trees, shrubs and exotic plants. He erected one of the first purpose-built orchid houses in the kitchen gardens, from 1836, an observatory, around 1851-2, was built close to the mansion house, and experiments with an electrically powered boat (built before 1848 by John himself) were conducted on the Lower Lake.