Before the Plantation of Ulster the area of Brookeborough was known as "Achadh Lon" (anglicised as "Aghalun"), the townland in which it lies. It is believed that the Irish name refers to a "field of blackbirds". Aghalun was in the hands of the Maguire Clan until the 1641 rebellion when it was given to the Brooke family. The village was then named after Sir Henry Brooke, who was granted the village in 1666 and settled at Colebrooke Park nearby.