Coordinates: 51°23′38″N 3°18′49″W / 51.3939°N 3.3136°W
Porthkerry Park is a large, public country park on the coast between Barry and Porthkerry in the Vale of Glamorgan in south Wales. It has fields, extensive woodland and nature trails, cliff-top pathways, a pebble-stone beach, and a small golf course. Architecturally, it is noted for the sixteen arch Porthkerry Viaduct crossed by a railway that served as a transportation for coal from the South Wales Valleys to the port in the late 19th and early 20th centuries. With the combination of green areas and the coastal location, the park is a popular destination for local primary schools taking their pupils on trips to study nature. The Egerton Grey Country House Hotel is also located in Porthkerry.
On the northern side of the park is the site of the old village at Cwmcidi (meaning Valley of the Black Dog), which came into existence before the middle of the 13th century. In 1622, Cwmcidi contained 5 houses bordering "Comkedye Street", interspersed with a number of tofts (dwelling sites) plus three scattered dwellings. By 1812, there remained only three cottages and a farmhouse. The cottages were finally swept away in the 1840s when the area was landscaped by the Romilly family to form Porthkerry Park. The name - although slightly anglicised - lives on in the area, in the form of a nearby public house, The Cwm Ciddy.