Frogmore is an estate within the Home Park, adjoining Windsor Castle, in Berkshire, England. It comprises 33 acres (130,000 m2), of primarily private gardens managed by the Crown Estate. It is the location of Frogmore House, a royal retreat, and Frogmore Cottage. The name derives from the preponderance of frogs which have always lived in this low-lying and marshy area near the River Thames. This area is part of the local flood plain. Its large landscaped gardens are Grade I listed on the Register of Historic Parks and Gardens.