King's Cross Thameslink station is a closed railway station in central London, England. It is located on Pentonville Road, around 250 metres (0.2 mi) east of King's Cross mainline station. At the time of closure, in 2007, it was served by Thameslink trains and managed by First Capital Connect.
The station opened in 1863 as King's Cross Metropolitan. It was one of the initial seven stations on the Metropolitan Railway, London's first underground line, which ran between Paddington and Farringdon. The Metropolitan had been planning for the station since 1851, when King's Cross mainline station was constructed, to provide a connection between the Great Western Railway at Paddington and the Great Northern Railway (GNR) out of King's Cross. Within a year of opening a pair of tunnels was added, which surfaced on the GNR just north of King's Cross and provided a direct rail connection between the two lines. In 1866 the line was extended east to Moorgate and Snow Hill tunnel was built to join the London, Chatham and Dover Railway (LCDR) City Branch at Ludgate Hill. In 1868 a second pair of tracks known as the City Widened Lines was opened along with a tunnel connection to the Midland Railway near St Pancras station. The route through the station was very busy throughout the remainder of the century, carrying trains from five companies. In 1892 the station was linked to the concourse of King's Cross mainline station by a foot tunnel.
The opening of the Piccadilly and Northern underground lines, as well as the growth of trams on the surface streets, led to a sharp reduction of services on the City Widened Lines in the early twentieth century. The Metropolitan line remained popular, however, following electrification of its tracks in 1905–06. Passenger service was reduced to peak hours only during World War I, with no service through the Snow Hill tunnel, as the lines were used heavily for freight and troop movements. The line and station were closed for five months during World War II, following damage in The Blitz. Only the City Widened Lines platforms remained in use when the station reopened in 1941: the Metropolitan line station was moved to a new pair of platforms which had been built at King's Cross St Pancras tube station, providing a shorter connection to the Piccadilly and Northern lines. Trains from the East Coast Main Line and Midland Main Line continued to stop at King's Cross Metropolitan. In the 1980s the City Widened Lines were electrified and the Snow Hill tunnel reopened to passenger traffic as part of the Thameslink programme. The station was renamed, first to King's Cross Midland City and then to its final name, King's Cross Thameslink. Service on the line grew and new destinations were added, and by the 2000s the station could no longer handle the passenger numbers. A new pair of platforms were built at St Pancras, and King's Cross Thameslink closed in 2007. The station was included in the London station group from the group's inception in 1983, and remained so until its closure.