The Tollman Garden, formerly known as the Sunken Garden, is one of several formal gardens arranged along the main terrace walk in the grounds of Ashford Castle. These gardens, laid out by the Guinness family in the nineteenth century, are amongst the finest of the many beautiful country house gardens to be found in Ireland.

In 1996 a circular pond, measuring eleven metres in diameter, was constructed in the centre of the rectangular lawn that was then known as the Sunken Garden, so called because of the high planted banks that surrounded it. The garden was approached down steps from the Velvet Garden to the east, and from a tunnel leading from the Walled Garden on the west, and also down steps from the Terrace Walk on the north side. It consisted only of a rectangular walkway leading around the lawn with no paths leading to the central pond.