Clapham Junction railway station is near St John's Hill in the south-west of Battersea in the London Borough of Wandsworth. Although it is in Battersea, the area around the station is commonly identified as Clapham Junction.
Many routes from London's two busiest termini, and , funnel through the station making it one of the busiest in Europe by number of trains using it, more than one hundred an hour outside peak periods. The station is also the busiest National Rail station for interchanges between services.
Before the railway came the area was rural and specialised in growing lavender; Lavender Hill is to the east of the station. The coach road from London to Guildford ran slightly south of the future station site, past The Falcon public house at the crossroads in the valley between St. John's Hill and Lavender Hill.
On 21 May 1838 the London and Southampton Railway, which became the London and South Western Railway (L&SWR) that day, opened its line from as far as Woking. That was the first railway through the area but it had no station at the present site.
When the station was built Battersea was regarded as a poor district while Clapham, a mile east, was more fashionable. The railway companies, to attract a middle- and upper-class clientele, adopted the grander of the two names, leading to a long-lasting misunderstanding that the station is in Clapham. A local action group, Love Battersea, was belatedly formed in 2005 to reduce the misapprehension.
Additional station buildings were erected in 1874 and 1876.
The station brought development to the surrounding area, the population of which rose from 6,000 in 1840 to 168,000 by 1910.