Steep Holm (Welsh: Ynys Rhonech, Old English: Ronech and later Steopanreolice) is an English island lying in the Bristol Channel. The island covers 48.87 acres (19.78 ha) at high tide, expanding to 63.26 acres (25.60 ha) at mean low water. At its highest point it is 78 metres (256 ft) above mean sea level. Administratively it forms part of the unitary authority of North Somerset within the ceremonial county of Somerset; between 1 April 1974 and 1 April 1996, it was administered as part of Avon. Nearby is Flat Holm island (Welsh: Ynys Echni), part of Wales.
Flat Holm (Welsh: Ynys Echni) is a Welsh island lying in the Bristol Channel approximately 6 km (4 mi) from Lavernock Point in the Vale of Glamorgan. It includes the most southerly point of Wales.
Flat Holm Lighthouse is 30 m (98 ft) high and 50 m (160 ft) above mean high water. It has a 100 watt lamp that flashes three times every ten seconds, and is red from 106° to 140°; white to 151°; red to 203°; white to 106°. White light visibility up to 33 km (18 nautical miles), this data as recorded in 1965 in Reed's Nautical Almanac but Trinity House now note visibility as 28 km (15 nmi) for the white light and 22 km (12 nmi) for the red light.
The English Stones are a rocky outcrop in the Severn Estuary between Caldicot, Monmouthshire, and Severn Beach, South Gloucestershire. Because the area is exposed at low tide, and is a rare spot of solid land in the highly tidal estuary, it has long been considered a good location to build barrages, dams or bridges. In the 1990s the construction of the Second Severn Crossing made use of the English Stones as a foundation for significant sections of the bridge.
Bideford Bay, also known as Barnstaple Bay and often shown on maps as Barnstaple or Bideford Bay, is a large area of water on the northwest coast of Devon in South West England, at the southwestern end of the Bristol Channel where it joins the Celtic Sea. The bay extends from Hartland Point in the southwest to Baggy point the northeast, and is partly sheltered by the island of Lundy, 12 miles (19 km) offshore. It takes its alternative names from the towns of Bideford and Barnstaple, located respectively on the rivers Torridge and Taw which flow into the bay. The alternative spelling Barnstable Bay, in use long after that spelling became obsolete for the town, is also sometimes seen.
Denny Island (Welsh: Ynys Denny; grid reference ST459810) is a small uninhabited rocky island of 0.24 hectares (0.6 acres), with scrub vegetation, in the Severn Estuary. Its rocky southern foreshore marks the boundary between England and Wales. Above high water mark, the island is reckoned administratively to Monmouthshire, South Wales. The island also marks the north-western limit of the City of Bristol's water boundary in the Severn estuary.