Guildford (/ˈɡɪlfərd/ (listen))^[1] is a town in Surrey, England, 27 miles (43 km) southwest of London on the A3 trunk road midway between the capital and Portsmouth.^[2][3]

The town has a population of about 80,000 and is the seat of the wider Borough of Guildford which had an estimated 147,889 inhabitants in 2018.^[4]

Guildford has Saxon roots^[5] and historians attribute its location to the existence of a gap in the North Downs where the River Wey was forded by the Harrow Way.^{[n 1]} By AD 978 it was home to an early English Royal Mint.^[7] The building of the Wey Navigation and the Basingstoke Canal in the 17th and 18th centuries, respectively, connected Guildford to a network of waterways that aided its prosperity.^[6] In the 20th century, the University of Surrey and the Anglican Guildford Cathedral were added.^[8]

Due to recent development running north from Guildford, and linking to the Woking area, Guildford now officially forms the southwestern tip of the Greater London Built-up Area, as defined by the Office for National Statistics.