The Halkyn Estate in North Wales comprises 1,800 acres lying between Pantasaph near Holywell and Rhosesmor. In recent years it has been designated both a Special Area of Conservation (SAC) and a Site of Special Scientific Interest (SSSI) but historically it has played a very significant role in the history of the Grosvenor Family.

With Halkyn once one of the most important sources of lead and zinc in the country, Richard Grosvenor purchased the mineral rights in 1601 and for more than 200 years the Grosvenors mined there very successfully.  It was the revenue from this activity which provided Sir Thomas Grosvenor with the money required to pay the dowry of Mary Davies in 1677. In marrying her, the Grosvenors acquired London’s famous 'five fields' to the north of the Thames which the family later developed to form Mayfair, Belgravia and Pimlico.

Today the Halkyn estate is no longer mined in this way. Instead, and with a great deal of the estate being common land, there is a public golf course on the estate whilst some outlying parts are being quarried for limestone by tenants.