Ham Hill is a hill and area of chalk downland in Wiltshire, England, on the steep banks running alongside the road from the village of Ham to Buttermere, close to the Berkshire border. A biological Site of Special Scientific Interest, notified in 1971, covers 1.5 hectares of the site; this designation is due to the site's species-rich plant and insect communities, which include some rare species. Notable among these is the musk orchid (Herminium monorchis), which has been confirmed at only one other site in Wiltshire.