Plantations in 16th- and 17th-century Ireland involved the confiscation of land by the English crown and the colonisation of this land with settlers from the island of Great Britain. There had already been smaller-scale immigration to Ireland as far back as the 12th century, which had resulted in a distinct ethnicity in Ireland known as the Old English, or Hiberno-Normans. Unofficial plantations carried out privately by landlords also took place, such as those in County Antrim and County Down.
The 16th-century plantations were established through large areas of the country by the confiscation of lands occupied by Gaelic clans and Hiberno-Norman dynasties, but principally in the provinces of Munster and Leinster. The Crown granted these lands to colonists ("planters") from England. This process began during the reign of Henry VIII and continued under Mary I and Elizabeth I. It was accelerated under James I, when the Plantation of Ulster took place on land escheated from those Gaelic chiefs who broke the terms of surrender and regrant, Charles I, and Oliver Cromwell; in their time, land was also granted to Scottish planters.
The early plantations in the 16th century tended to be based on small "exemplary" colonies. The later plantations were based on mass confiscations of land from Irish landowners and the subsequent importation of numerous settlers and labourers from England and Wales, and later from Scotland.