Attractions include a medieval feast, a Georgian village fete, a Rebecca Storm concert, and an antiques roadshow.
Other events will include garden tours, craft exhibitions, archery, falconry, sumptuous dining, talks, and a seminar with renowned academics, as well as a Fitzgerald rally, genealogy, river cruises, life-size puppetry, local food, drink, song, dance, and storytelling.
Current incumbent Barbara Grubb of the Villiers-Stuarts represents the 26th generation of the family to reside at the property.
The estate is perched in protective isolation amid 600 acres of forestry beside the Blackwater.
Dromana House traces an intriguing lineage of lords, barons and viscounts, including female succession, through the clan Fitzgerald.
The July celebrations are “not-for-profit”, said Ms Grubb “but hopefully will showcase the house and the region”.
Sponsors include Fáilte Ireland, Waterford City and County Council and nearby Camphire House and Horse Farm, with local community and businesses also involved.
The Thursday, July 2 programme focuses on tours and stories of prominent west Waterford houses, extending to a walking tour of Youghal.
On the Friday, 800 years to the day since King John granted Waterford and Desmond lands to Thomas FitzAnthony, a Fitzgeralds rally takes place at Dromana House, with the 9th Duke and Duchess of Leinster in attendance.
An Australian councillor, Graham Piddock, from Dromana in New South Wales, will plant a cherry tree in deference to the legend that Katherine Fitzgerald, Countess of Desmond, died by falling from a cherry tree in 1604. A new, cross-hybrid rhododendron, officially named Dromana 800, will also be revealed.
Dromana House lawn hosts the medieval feast (€45) on the Saturday night, with “organic hog roast”, local whiskey, song, and dance.
It follows a commemoration in Cappoquin of the Battle of Affane, while Rebecca Storm will perform at Villierstown Church.