Question: What castle in Ireland once occupied by the MacDonnells is accessible by a bridge?

full_context: Document 1: Dunluce Upper: Dunluce Upper (Irish: "Dún Libhse Uachtarach" ) is a barony in County Antrim, Northern Ireland. It is bordered by six other baronies: Dunluce Lower to the north; Cary to the north-east; North East Liberties of Coleraine to the north-west; Coleraine to the west; Kilconway to the south; and Glenarm Lower to the east. Dunluce Upper also formed part of the medieval territory known as the Route.
Document 2: Ballylough Castle: Ballylough Castle is a ruined castle in County Antrim, Northern Ireland, that was a stronghold of the MacQuillans and the MacDonnells in former times.
Document 3: Ballyclare: It sits on the river Six Mile Water. The town probably owes its origins to its being a crossing point of the river, the strategic importance of which is shown by existence of a small Norman motte on the south side of the river and presently located in the War Memorial Park. The broad main street dates from the 17th century. In the centre of the town is the Market Square with the Town Hall. The town grew in the 19th century with the coming of the railway and it became an important industrial town with a large paper mill in the South West of the town and a large Linen Bleach Green . These factories gave their names to the roads leading to them, the Mill Road and the Green Road, but have been closed for some time. It is now a local service centre with a significant dormitory role in relation to Belfast. It is the main focus within the rural area for shopping, education and recreation. To the north is the remnant of Craig Hill, which once provided a wooded backdrop but is now covered with modern housing. Much of the Craig Hill has been quarried for its basalt.
Document 4: Greencastle, County Down: Greencastle is a castle in County Down, Northern Ireland. It is a royal castle built in the 13th century. While it dates mainly from the 13th century, it had substantial 15th- and 16th-century alterations. The large rectangular keep with three vaulted chambers at the ground floor is approached across a rock-cut ditch. It was originally surrounded by outer rectangular walls with four corner towers (ruins of some remain). It is likely to have been built by Hugh de Lacy, along with Carlingford Castle on the opposite side of Carlingford Lough, to guard the narrow entry channel to the Lough, and the ferry crossing between the two.
Document 5: Ardrossan Castle: Ardrossan Castle is situated on the west coast of Scotland in the town of Ardrossan, Ayrshire. The castle, defended by a moat, stands on a ridge above the town. There is a keep dating from the fifteenth century, and a vaulted range containing a kitchen and cellars. In a deep passageway there is a well. Part of the keep remains up to the corbels of the parapet, but it is in ruins. The original castle, owned by Clan Barclay, was partly destroyed during the Wars of Scottish Independence. This event, in which the English garrison were slaughtered, became known as "Wallace's Larder," a name which is still applied to the remaining vaults. Rebuilt by Clan Montgomery in the 15th century, Ardrossan later fell into disuse and was partially demolished by the soldiers of Oliver Cromwell in the 17th century who used the stones to help construct the Ayr Citadel.
Document 6: Bass Rock: The Bass Rock, or simply the Bass ( ), is an island in the outer part of the Firth of Forth in the east of Scotland. Approximately 2 km offshore, and 5 km north-east of North Berwick, it is a steep-sided volcanic rock, 107 m at its highest point, and is home to a large colony of gannets. The rock is uninhabited, but historically has been settled by an early Christian hermit, and later was the site of an important castle, which after the Commonwealth period was used as a prison. The island belongs to Sir Hew Hamilton-Dalrymple, whose family acquired it in 1706, and before to the Lauder family for almost six centuries. The Bass Rock Lighthouse was constructed on the rock in 1902, and the remains of an ancient chapel survive.
Document 7: MacDonnell of Antrim: The MacDonnells of Antrim (Gaelic: "Mac Domhnaill"), also known as the MacDonnells of the Glens, are a branch of the primarily Scottish-based Clan Donald in Ireland. Initially part of Clan MacDonald of Dunnyveg (Clan Donald South), the MacDonnells of Antrim became their own branch in 1558 when Somhairle Buidhe MacDonnell obtained the lordship of the territory in Ireland from James MacDonald, 6th chief of the Clan MacDonald of Dunnyveg. The MacDonnells of Antrim were a sept of the powerful Clan Donald of the royal Clann Somhairle, (see Lords of the Isles), that the English crown had attempted to cultivate since the early 14th century in its efforts to influence the course of politics in Scotland. The MacDonnells established a growing presence in Ireland throughout the 15th and 16th centuries, and played a crucial role in the politics of 17th century Ireland. Today the surname is predominantly spelled McDonnell in Ireland and abroad. Many of the present day McDonnells have a common descent from Sorley Boy MacDonnell.
Document 8: Blackwater Castle: Blackwater Castle (Castle Widenham) is a privately owned estate located in the village of Castletownroche between the towns of Mallow and Fermoy in North Cork, Ireland, and since 2005 is available to rent as a private hire venue for castle weddings and private parties along with castle rentals for vacations. The castle comprises one of the oldest occupied castles in Ireland as parts of the residential section date back to the early 15th century while the castle structure itself dates back to the 12th century. A round tower on the eastern end of the Castle dating from the late 12th century is still standing although no longer accessible. The castle was constructed on the ancient fortress of Dun Cruadha, an inland promontory fort dating back to the late Bronze Age/early Iron Age, while the site itself was first occupied back in the Mesolithic age (circa 9,000 years ago) as evidenced by the flint scatter found at Kilcummer and the caves on the south bank of the River Awbeg making this site one of the earliest known settlements in Ireland.
Document 9: Seagate Castle: Seagate Castle is a castle in North Ayrshire, in the town of Irvine, close to the River Irvine, Scotland. The castle was formerly a stronghold, a town house, and later a dower house of the Montgomery Clan. The castle overlooks the oldest street in Irvine, which was once the main route between the town and the old harbour at Seagatefoot, which by 1606, was useless and abandoned due to silting. The remains of the castle are protected as a scheduled ancient monument.
Document 10: Dunvegan Castle: Dunvegan Castle is located 1 mi to the north of Dunvegan on the Isle of Skye, off the west coast of Scotland. It is the seat of the MacLeod of MacLeod, chief of the Clan MacLeod. Probably a fortified site from the earliest times, the castle was first built in the 13th century and developed piecemeal over the centuries. In the 19th century the whole was remodelled in a mock-medieval style. The castle is built on an elevated rock overlooking an inlet on the eastern shore of Loch Dunvegan, a sea loch.
Document 11: Dunluce Castle: Dunluce Castle (from Irish: "Dún Libhse" ) is a now-ruined medieval castle in Northern Ireland. It is located on the edge of a basalt outcropping in County Antrim (between Portballintrae and Portrush), and is accessible via a bridge connecting it to the mainland. The castle is surrounded by extremely steep drops on either side, which may have been an important factor to the early Christians and Vikings who were drawn to this place where an early Irish fort once stood.
Document 12: Carra Castle, Antrim: Carra Castle or Castle Carra (Irish: "Caisleán Carrach" ) is a ruined castle, just north of Cushendun, County Antrim, Northern Ireland. It dates to around the early 14th century. The castle lies in a field near the coast and the harbour of Cushendun, known as Murlough Bay. The site had once been used during medieval times as a children's cemetery.
Document 13: Glenarm: Dating back to Norman times, the village is the family seat of the MacDonnells, who once occupied Dunluce Castle on the north coast. The village is now a Conservation Area, and its main street (Altmore Street) leads directly to Glenarm Forest, from which can be seen Glenarm Castle, on the far bank of the little river which runs through the village to the sea. The imposing entrance to Glenarm Castle, the Barbican Gate, is at the heart of the village. The Castle dates from 1750, with early 19th century alterations. Glenarm claims to be the oldest town in Ulster, having been granted a charter in the 12th century. The Barbican Gate to Glenarm Castle was restored by the Irish Landmark Trust, a conservation charity that saves buildings that are at risk of being lost.
Document 14: Dunaneeny Castle: Dunaneeny Castle (or "Dunineny Castle", Irish "Dún an Aonaigh") is a ruined castle near Ballycastle, Antrim, Northern Ireland. The castle was home to the chiefs of Clan MacDonald of Dunnyveg and later the MacDonnells of Antrim.
Document 15: Tantallon Castle: Tantallon Castle is a semi-ruined mid-14th-century fortress, located 5 km east of North Berwick, in East Lothian, Scotland. It sits atop a promontory opposite the Bass Rock, looking out onto the Firth of Forth. The last medieval curtain wall castle to be constructed in Scotland, Tantallon comprises a single wall blocking off the headland, with the other three sides naturally protected by sea cliffs.
ground_truth: Dunluce Castle