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, London Waterloo and London Victoria, 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.
Each day about 2,000 trains, most stopping, pass through the station, more than through any other station in Europe. At peak times 180 trains per hour pass through of which 117 stop. It is not the busiest station by number of passengers, most of whom (about 430,000 on a weekday, of which 135,000 are at rush hours) pass through. Interchanges make some 40% of the activity and on that basis too it is the busiest station in the UK.
In 2011, the station had three entrances, all with staffed ticket offices, though only the south-east entrance is open 24 hours a day. The most heavily used of the three, this leads from St John's Hill via a small indoor shopping centre, into a subway some 15 ft (4.6 m) wide that connects to the eastern ends of all platforms.
The north entrance, which has restricted opening hours, leads from Grant Road to the same subway. The subway is crowded during rush hours, with the ticket barriers at the ends are pinch points.