Sevenoaks is a commuter town situated in western Kent, England, south-east of Charing Cross, on a commuter main line from the capital. The town gives its name to the Sevenoaks district, of which it is the principal town, followed by Swanley and Edenbridge. The presence of Knole House, a large mansion, led to the earlier settlement becoming a village and in the 13th century a market was established. Sevenoaks became part of the modern communications network when one of the earlier turnpikes was opened in the 18th century; the railway was relatively late in reaching it. It has a large commuting population although the nearby Fort Halstead defence installation is a large local employer. Located to the south-east of the town is Knole Park, within which lies Knole House. There are several educational establishments in the town, including the independent Sevenoaks School and Knole Academy.