The estate was sold to the Ministry of Agriculture by Robert Jocelyn, 8th Earl of Roden in 1930 and 1941. Covering an area of 630 hectares at the foot of the Mourne Mountains, the forest park offers panoramic views of the surrounding mountains and the sea at nearby Newcastle. The forest has several walking trails sign posted by different coloured arrows, the longest being the "long haul trail" at 8 miles long. The river Shimna flows through the park. Tollymore was listed in The Sunday Times top twenty British picnic sites for 2000.
The Hamilton family remained owners of Tollymore until 1798 when a similar chain of events took place.
The great grandson of William Hamilton, James died in 1798 without children and Tollymore was transferred to his sister Anne, who married Robert Jocelyn, 1st Earl of Roden.
The Roden family continued in possession of Tollymore throughout the 19th Century, when in 1930 the late Earl sold part of the estate to the Ministry of Agriculture for afforestation purposes. The remainder was sold to the Ministry in 1941.