Which river flows by Windsor Castle?

The River Thames flows by Windsor Castle in Windsor, England.

Windsor Castle stands in Berkshire on elevated ground overlooking the Thames, one of Britain's most important rivers. The river passes near the castle and separates Windsor from the town of Eton, home of the historic Eton College. The castle's position was strategically valuable because the Thames was a major route into the interior of England.

William the Conqueror commissioned the original Windsor fortification in the decade after the Norman Conquest of 1066. Its location helped protect the western approach to London and gave the monarchy access to both the river and the surrounding royal hunting forest. The original earth-and-timber castle was later transformed into the substantial stone complex seen today.

The Thames is often confused with the River Wey in questions about the wider Windsor area, but the river directly associated with Windsor Castle is the Thames. London lies farther downstream, while the river continues westward toward Reading and beyond.