The Darry castle and lands are modest, situated half a day south of the Trident and likely close to a river known as the Darry. The Darrys were one of the few riverland houses who fought on the Targaryen side, having been high in King Aerys’s favor. Ser Jonothor Darry was one of the Kingsguard and died at the same battle where Robert Baratheon killed Prince Rhaegar. Ser Willum Darry helped the queen and her children escape from King’s Landing and then, after the birth of Danaerys and the death of the queen, took the children to safety in Braavos. He died there from illness. This loyalty to the Targaryens led to the house’s wealth and power being disbursed to others who had fought for the newly-crowned Robert.
In older days, one of the great Lord Commanders of the Kingsguard was the Demon of Darry. The house is ruled by Lord Darry, with his heir being Ser Raymun Darry and his heir in turn being Lyman Darry, a boy of about 8 or 9 years.
Information about House Darry that reveals spoilers from the books.