Dún Laoghaire-Rathdown County Council has completed the purchase of the Fernhill Estate in Sandyford, Co Dublin for €4.25 million.
A council spokesman said there were plans to redevelop the 83-acre site as a public park in the coming years.
The property was bought by developer David Arnold for about €45 million in 2008 and later taken over by Nama. It went on the market in April through Colliers at a guide price of €5 million.
Council chairwoman Marie Baker said the acquisition was one of the last opportunities for the council to buy a "sizeable parcel of land" to be used for recreational purposes.
The area is located 11km south of Dublin on the Enniskerry Road, between Sandyford and Stepaside.
Valuable gardens
Fernhill gardens were started in the early 19th century and developed by their owners through the decades.
The gardens have rare collections of plants, trees and shrubs. About 45 acres of the land is wooded.
The property was owned by the Walker family from 1934 onwards.
Councillors will be presented with the plans, which will also include future uses of the house, for their consideration in a few months.
The house was initially built in 1723.
