Bull Island (), more properly North Bull Island ( who wrote An Irish Sanctuary – Birds of the North Bull (1953), to apply for Bull Island to be made a sanctuary by the government.
Situation
thumb|Star of the Sea statue
The island is connected to the mainland by the Bull Bridge, today a one-lane wooden road bridge (with weight and height restrictions) at the southern (Clontarf/Dollymount) end, and by a broad causeway at Raheny, approximately halfway along, and forms part of Raheny and Clontarf districts.
Most of North Bull Island is property of Dublin City Council, after the buying-out of interests such as the Howth Estate, exceptions having included the Bull Wall, the breakwater beyond it, and the wooden bridge to it, which were owned by the Dublin Port Company (and closed for a day each year to ensure that no right of way was created), and the Royal Dublin Golf Club links, only the latter remaining. St. Anne's Golf Club rent from the Council. The bulk of the island comprises the largest park owned by the city.
There are just a few residents on the island, in houses beside the wooden bridge built by the Dublin Port Company for its employees. In addition to the clubhouses of the two golf clubs, there is the newly re-built Sea Scout den at the Clontarf end, and a small cafe.
At the end of the North Bull Wall is the Star of the Sea (Réalt na Mara) statue, funded by Dublin Port workers and sailors, and dedicated by the then archbishop of Dublin in 1972.
Continuing development
The island continues to grow and it is a possibility that within the next half-century continued deposition may lead to its merging with the mainland at Red Rock in Sutton, forming a lagoon, changing the make-up of the area's wildlife and landlocking two dinghy sailing clubs. However, the risk of this is considered small due to the strength of currents and depth of water in Sutton Channel.
Geology and hydrology
thumb|Bull Island Interpretative Centre
The island is primarily a sand structure approximately 5 km long and under 1 km wide. The southeast-facing side is a flat beach, Dollymount Strand, backed by marram-grass-anchored dunes, scrub and marsh. On the northern side of the Bull, between the island and the mainland, is a large linear saltmarsh complex backed by mudflats all of which are covered at high tide. Several of the city's small rivers and streams enter the bay here, notably the Naniken River, the Santry River, Fox Stream, Blackbanks Stream and Daunagh Water. Furthermore, the city's second-largest river by volume, the River Tolka, has its estuary facing the city end of the island, into which the Wad River, and a combination of several smaller watercourses, also flow.
Fauna
Birds
alt=A photo of a wetland area. There is a collection of Brant geese on the ground. One is flapping its wings.|thumb|A group of [[Brant (goose)|Brant on Bull Island in November 2024.]]
A wide range of birds visit Bull Island, with a more limited set nesting there; most are either winter feeders, or pass through in spring and autumn. Wading species include Eurasian curlews, Eurasian oystercatchers and redshanks, while others include shelduck, teal, pale-bellied brent geese, and various gulls. Also encountered are grey plovers, bar-tailed godwits, northern shovellers, little egrets, reed buntings, Common cuckoos and little terns.
Mammals
There were a number of terrestrial mammal species on the island for decades, with one becoming extinct in the 2010s and one added. Species include the pygmy shrew, brown rat, red fox, field mouse, hedgehog, European rabbit and Irish hare, no hare has been seen since 2016. During a study of hares on the island during the 1990s, it was concluded that poor breeding success due to disturbance from people and, more seriously, dogs, was the main cause of the drop-off in numbers. Hares were more vulnerable than other species as they do not shelter in burrows; they are also active in the daytime.
Amphibians
The common frog has a stable and substantial presence on the island. It is also a National Special Amenity Area [https://web.archive.org/web/20141129062703/http://www.conserveireland.com/saao.php] since 1995, one of 3 in Ireland. This recognises both its outstanding beauty and nature conservation values.
Intrepretative centre
There is an Interpretative Centre at the end of the causeway on the right-hand side which has displays and information on the flora and fauna of the island, and there are also information signs to either side of the causeway access, and on the roundabout where the causeway road approaches the beach. The Centre was opened in 1986 and provides a base for many schools and educational groups to visit the Island. It was funded by the European Commission and the Dublin Rotary Club.
Leisure activities
Walking
thumb|Learning to drive on [[Dollymount|Dollymount Strand ]]
Dollymount Strand, the 5 km beach on the island, is a popular walking and recreational area. The walking of dogs is also popular, though they are supposed to be kept under control, due to the National Nature Reserve status, and in particular to fears of attacks on rabbits and hares. It is possible to walk a circuit that includes the beach and St. Anne's Park.
Driving
Many people learned to drive on the firm flat sandy foreshore at low tide; there are even (very low) speed limits posted on the beach. For about two decades, access by car was limited to a portion of the island near the Bull Bridge and two sections reached from the causeway at Raheny, the latter having ceased in 2016.
Swimming
thumb|Bathing shelter on the Bull Wall
The strand is historically a popular swimming spot but usage fell sharply as pollution rose in the 1980s, mainly due to sewage and stormwater pollution. There are a series of bathing shelters and lifeguard stations that were designed by Herbert Simms in his role as Dublin Corporation Housing Architect. In July 2021, Dublin City Council demolished one of Simms' lifeguard stations dating from 1934 without notice, citing ongoing issues with anti-social behaviour at the abandoned structure.
Following the Dublin Bay Water Quality Management Plan programme in the 1990s, there were significant improvements to water quality and in 2006 it was awarded the Blue Flag status for the first time. The area has lost and held Blue Flag status in the years since then. Water quality continues to be affected by several issues, including lack of capacity of existing sewage treatment facilities, excess nutrients flowing into Dublin Bay from the River Liffey and other watercourses, and stormwater pollution.