Islandmagee is a peninsula and civil parish on the east coast of County Antrim, Northern Ireland, located between the towns of Larne and Whitehead. It is part of the Mid and East Antrim Borough Council area and is a sparsely populated rural community with a long history since the mesolithic period. The population is approximately 2,500. In the earl…Islandmagee is a peninsula and civil parish on the east coast of County Antrim, Northern Ireland, located between the towns of Larne and Whitehead. It is part of the Mid and East Antrim Borough Council area and is a sparsely populated rural community with a long history since the mesolithic period. The population is approximately 2,500. In the early medieval period it was known as Semne, a petty-kingdom within Ulaid.