Prehen (possibly from Irish preachan, meaning 'place of the crow'[1]) is a small townland and estate outside the city of Derry, County Londonderry, Northern Ireland.

[2] Before the Plantation of Ulster in the early seventeenth century, Prehen was in the freehold of Captain Manus O'Cahan but was taken over by the Goldsmiths' Company of London.

It was to Prehen House that John MacNaghten, later to be known as "Half-Hung" came, originally as a guest and friend of Knox, whose only daughter Mary Ann he tricked into an arranged marriage so that he could gain her dowry.

MacNaghten, infuriated, but believing himself entitled to Mary Ann's £5000 marriage dowry, cursed the girl's father and swore bloody revenge on Knox and all his family in front of several witnesses and set in motion a plan to abduct the girl and then consummate the marriage, after which he believed Knox would have no choice but to hand over the money.

Life at Prehen House continued, and each year on the anniversary of Mary Ann's death, her mother would retire to her room to lament her daughter's fate and would not emerge until the next day.

She eventually recovered from her grief with the marriage of Mary Ann's brother George to Jane Mahon of Strokestown, County Roscommon, and this girl became as a second daughter to her.

Two other small estates located in the Prehen area are Dunwood and Stoneywood, the latter built in 2001 with fields purchased from Glover(farmer).

Prehen House was acquired in 1971 by its current owners, the Peck family, formerly of Rathbeale Hall, who have since restored and revived it, officially opening it to the public in September 2004.