In 1975 the last remaining trees of the Dalton's former orchard were removed. Approximately 12,000 trees have by now been planted by the Golf Club. In 1976 the Club celebrated the centenary of Duntryleague with a week long programme of festivities. Duntryleague was listed on the Register of the National Estate. In 1980 Orange Golf Club sold portions on southern boundary for Orange High School and new residential development, leaving . In 1981 financial assistance from the NSW Heritage Council was sought to paint and do exterior maintenance of the guesthouse, gate house and front gates. Between 1982 and 1985 the clubhouse was refurbished, including the dining room, a new bar was installed, recarpeting the bar and the Brennan Room's dance floor, refurbishing the guesthouse including bedrooms with period furniture, new carpet and modernised facilities. The guesthouse kitchen was renovated. Designers Cairncross, Scheer & Associates were responsible for the work. Five blocks of land on the property were sold to help finance improvements. In 1984 Duntryleague was made subject to a Permanent Conservation Order under the NSW Heritage Act. This was transferred onto the NSW State Heritage Register on its creation with amendment of the legislation in 1998. In 2002 architect Christo Aitken was engaged to assist with grant funding and to prepare a conservation management plan for the property. Duntryleague is sited on the top of a hill among magnificent trees. In 1875-9 holdings comprised . Several outbuildings were built on the estate, including two gate houses, on Forbes and Woodward Roads. The gatekeeper employed by Dalton, Leon Ravat, was a French vintner who made wines from the grapes grown in the extensive vineyards of the property. Irrigation was facilitated by a deep well and windmill that dew water from 90 feet below the ground. The Banjo Patterson Memorial on the road to Clifton Grove is one of the original gate posts of Duntryleague. In 1880 the property expanded to with the realignment of Cargo Road and subsequent purchase of this portion. In Dalton employed Alfred Andrew Patterson (1859-1932) as a gardener at Duntryleague which had magnificent grounds. Through Dalton's influence Patterson became the inaugural gardener (in 1887) at Cook Park, Orange and was subsequently head gardener at Machattie Park, Bathurst, for 20 years of a formative period in its development. In 1906 land to north of Forbes Road transferred to ownership of the Dalton estate. During Dalton's ownership most of the native trees on the land were cleared and imported trees, primarily pines (Pinus spp.) had been planted along the drive, near the hose and along the Woodward Street boundary.