King's Cross Thameslink station is a closed railway station in central London, which served the Thameslink route. It was replaced by new Thameslink platforms at St Pancras in December 2007. The last operator of the station was First Capital Connect. The site is on Pentonville Road, about 150 m (160 yd) from King's Cross station.
The station occupied part of the original site of the Metropolitan Railway's 1863 King's Cross station. Its original street buildings were a little further west than the later station frontage and, though in poor repair, may still be seen. The Thameslink platforms on the City Widened Lines were separated only by a newer wall from the site of the Underground platforms, which may still be seen on the west side from Underground trains travelling between King's Cross St. Pancras and Farringdon stations.
The two platforms at King's Cross Thameslink were designated A and B, in contrast to the platform numbers used at most other stations. This avoided confusion with the platforms at nearby King's Cross, which may have been regarded as part of the same station complex. A similar situation exists at Waterloo East station, an annexe of London Waterloo, and the use of platform letters has been continued on the new Thameslink platforms at St Pancras.
The Thameslink platforms were linked directly by stairs and a tunnel to the Victoria and Piccadilly line platforms at King's Cross St. Pancras, and via both sets of platforms to the Circle, Hammersmith & City, Metropolitan and Northern lines.