Local legend associates the horse with St George and the Dragon, hence the name of nearby Dragon Hill. This is a round mound, about 10 metres high with a flattened top, likely to have been formed by glacial erosion.
The Iron Age hillfort known as Uffington Castle can be found at the summit of Whitehorse Hill. This large enclosure, measures 220 metres by 160 metres, surrounded by a wide chalk-stone bank or inner rampart about 12 metres wide and 2.5 metres high, and formerly lined with sarsen (sandstone) stones.
Around this is a grass-covered ditch about 3 metres deep and a further, smaller bank forming an outer rampart. A causeway, flanked by the out-turned ends of the inner rampart, provides an entrance to the site from the west. This would have been closed by a gate.
Large Iron Age hillforts are rare. Most are located on the high chalklands of the southern counties of England, and Uffington Castle is regarded as an outstanding example.