Largest inhabited-castle grounds

Balmoral Castle in Royal Deeside, Aberdeenshire, UK, incorporates approximately 50,000 acres (20,230 hectares) of land. The Queen and Prince Philip still stay at Balmoral at least once a year, for their summer break. The original castle and estate was purchased by the Crown in 1852. The castle that stands today was completed in 1856, to a design by Prince Albert, Queen Victoria’s consort, and the Scottish architect William Smith; the original castle was demolished.

Balmoral remains a working estate, including farmland, grouse moors and forest as well as herds of ponies, Highland cattle and deer. For reference, one source (Scottish-places.info) states that the grounds of the castle extend for precisely 21,600 hectares ha (53,375 acres).