The townland of Doon (from Irish Dún meaning- The Fort) in the civil parish of Tomregan is in the electoral district of Ballyconnell.
Its chief geographical features are the Shannon-Erne Waterway, mountain streams and some drumlin hills reaching an altitude of 200 feet (61 m) above sea-level.
An Inquisition held in Cavan Town on 20 September 1630 stated that Walter Talbot's lands included one poll each in Downe and Enagh.
[8] James Talbot married Helen Calvert, the daughter of George Calvert, 1st Baron Baltimore of Maryland, USA, in 1635 and had a son Colonel George Talbot who owned an estate in Cecil County, Maryland which he named Ballyconnell in honour of his native town in Cavan.
The only inhabitants of Ballyconnell who paid the Hearth Tax in the 1664 Hearth Money Rolls were Thomas Gwyllym, John Squire, Henry Jordan and Denis Alarne, but this would have included both Doon and Annagh townlands as Thomas Gwyllym was the owner of Ballyconnell Castle and lived in Annagh.
A deed dated 2 May 1724 by the aforesaid Meredith Gwyllym includes the townland as Down alias Enoch.
[11] The Gwyllym estate was sold for £8,000 in 1724 to Colonel Alexander Montgomery (1686–1729) of Convoy House, County Donegal, M.P.
In 1856 they sold the estate to take advantage of its increased value owing to the opening of the Woodford Canal through the town in the same year.
The estate, including Doon, was split up among different purchasers and maps & details of previous leases of the sold parts are still available.
The losing candidates were George Montgomery (MP) of Ballyconnell and Barry Maxwell, 1st Earl of Farnham.
[16] In 1832 one person in Doon was registered as a keeper of weapons- Ralph Montgomery, who had one gun, one pistol and two swords.
[18][19] The 1841 Census of Ireland gives a combined population of 671 for Doon and Ballyconnell, of which 333 were males and 338 were females, with 127 houses, of which 12 were uninhabited.
The 1851 Census of Ireland gives a combined population of 667, a decrease of 4 on the 1841 figure, due to the intervening Irish Famine of 1845–47, of which 331 were males and 336 were females, with 119 houses, of which 7 were uninhabited.