Carrickfergus (from Irish: Carraig Fhearghais, meaning "rock of Fergus"), known locally and colloquially as "Carrick", is a large town in County Antrim, Northern Ireland. It is located on the north shore of Belfast Lough, 11 miles (18 km) from Belfast. The town had a population of 27,903 at the 2011 Census and takes its name from Fergus Mór mac Eirc, the 6th-century king of Dál Riata. It is County Antrim's oldest town and one of the oldest settlements in Ireland as a whole. Carrickfergus was the administrative centre for Carrickfergus Borough Council, before this was amalgamated into the Mid and East Antrim District Council in 2015, and forms part of the Belfast Metropolitan Area. It is also a townland of 65 acres, a civil parish and a barony.
The town is the subject of the classic Irish folk song "Carrickfergus", a 19th-century translation of an Irish-language song (Do Bhí Bean Uasal) from Munster, which begins with the words, "I wish I was in Carrickfergus."
The British peerage title of Baron Carrickfergus, which had become extinct in 1883, was bestowed upon Prince William on his wedding day on 29 April 2011.