Cookstown is a town and townland in County Tyrone, Northern Ireland. It is the fourth largest town in the county and had a population of nearly 11,000 people in the 2001 Census. It is one of the main towns in the area of Mid-Ulster. It was founded around 1620 when the townlands in the area were leased by an English ecclesiastical lawyer, Dr. Alan Cooke, from the Archbishop of Armagh, who had been granted the lands after the Flight of the Earls during the Plantation of Ulster.