Guildford (/ˈɡɪlfərd/ (listen)) is a town in west Surrey, around 27 mi (43 km) southwest of central London. As of the 2011 census, the town has a population of about 77,000 and is the seat of the wider Borough of Guildford, which had around 148,998 inhabitants in 2019. The name "Guildford" is thought to derive from a crossing of the River Wey, a tributary of the River Thames that flows through the town centre.
The earliest evidence of human activity in the area is from the Mesolithic and Guildford is mentioned in the will of Alfred the Great from c. 880. The exact location of the main Anglo-Saxon settlement is unclear and the current site of the modern town centre may not have been occupied until the early-11th century. Following the Norman Conquest, a motte-and-bailey castle was constructed, which was developed into a royal residence by Henry III. During the late Middle Ages, Guildford prospered as a result of the wool trade and the town was granted a charter of incorporation by Henry VII in 1488.
The River Wey Navigation between Guildford and the Thames was opened in 1653, facilitating the transport of produce, building materials and manufactured items to new markets in London. The arrival of the railways in the 1840s attracted further investment and the town began to grow with the construction of its first new suburb at Charlotteville in the 1860s. The town became the centre of a new Anglican diocese in 1927 and the foundation stone of the cathedral was laid in 1936. Guildford became a university town in September 1966, when the University of Surrey was established by Royal Charter.
Guildford is surrounded on three sides by the Surrey Hills Area of Outstanding Natural Beauty, which severely limits its potential for expansion to the east, west and south. Recent development has been focused to the north of the town in the direction of Woking. Guildford now officially forms the southwestern tip of the Greater London Built-up Area, as defined by the Office for National Statistics.