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. They followed 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. Unofficial plantations carried out privately by landlords also took place such as that of Antrim and Down.
The 16th-century plantations were established throughout the country by the confiscation of lands occupied by Gaelic clans and Hiberno-Norman dynasties, but principally in the provinces of Munster and Ulster. 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, 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.
The final official plantations were established under the English Commonwealth and Cromwell's Protectorate during the 1650s, when thousands of Parliamentarian soldiers were settled in Ireland. Apart from the plantations, significant immigration into Ireland continued well into the 18th century, from both Great Britain and continental Europe.