It is on the Brighton Main Line, 20 miles 59 chains (33.4 km) measured from London Charing Cross, and train services are currently provided by Southern, who manage the station, and Thameslink.

It was opened by the L&BR on 1 December 1841, and from 1842 it was also used by SER and was the point at which travellers between the two railways exchanged trains.

The section of line between Coulsdon and Redhill was transferred to SER operation, and the new owners decided to close Merstham station on 1 October 1843, thereby forcing passengers wishing to change trains to walk between the two stations at Redhill.

The up side booking office (badly damaged by fire in the late 1980s and later rebuilt) and footbridge date from a 1905 rebuilding.

In addition, the Peterborough to Horsham service also reduces to hourly and northbound, runs only as far as London Bridge.