Farnham is a market town in Surrey, England, within the borough of Waverley. The town is 36 miles (58 km) southwest of London in the extreme west of Surrey, adjacent to the border with Hampshire. By road, Guildford is 11 miles (17 km) to the east and Winchester a further 28 miles (45 km) along the same axis as London. Farnham is the largest town in Waverley; it is one of the five largest conurbations in Surrey. It is of historic interest, with many old buildings, including a number of Georgian houses. Farnham Castle overlooks the town. A short distance south-east of the town centre are the ruins of Waverley Abbey, Moor Park House, Northbrook Park and Mother Ludlam's Cave. Farnham is twinned with Andernach in Germany. It is drained by the River Wey (North Branch) which is navigable only by canoe at this point.