Stirling Castle, locate in Stirling, is one of the largest and most important castles, both historically and architecturally, in Scotland. The Castle sits atop the Castle Hill, a volcanic crag, which forms part of the Stirling Sill geological formation. It is surrounded on three sides by steep cliffs, giving it a strong defensive position. Its strategic location, guarding the crossing of the River Forth, has made it an important fortification from the earliest times. The Castle is a Scheduled Ancient Monument, and is managed by Historic Scotland.