Lambay Island, often simply Lambay, is an island in the Irish Sea off the coast of north County Dublin, Ireland. The largest island off the east coast of Ireland, it is four kilometres (2 mi) offshore from the headland at Portrane, and is the easternmost point of the province of Leinster. Of volcanic origin, it has been inhabited since the prehistoric period and has been the subject of multiple archaeological studies. Lambay has notable populations of seabirds, a range of local fauna, some not found elsewhere in Ireland, and a colony of wallabies, as well as more than 300 plant varieties, and was the subject of major studies of flora and bird, and a major multidisciplinary study of flora and fauna between 1905 and 1907. The island is privately owned by a trust for members of certain branches of the Baring family and managed by the current Baron Revelstoke. It has a very small permanent population and few buildings but hosts some day visitors and short-stay guests, and there is a working farm.