Guildford is a town in west Surrey, England, around 27 mi (43 km) southwest of central London. As of the 2011 census, the town had a population of about 77,000; it is the seat of the wider Borough of Guildford, which had around 151,359 inhabitants in 2024. Its name is thought to derive from a crossing of the River Wey, a tributary of the River Thames, that flows through the town centre.