The station was constructed by the Midland Railway (MR), which had an extensive rail network across the Midlands and the North of England, but no dedicated line into London. After rail traffic problems following the 1862 International Exhibition, the MR decided to build a connection from Bedford to London with its own terminus. The station was designed by William Henry Barlow and constructed with a single-span iron roof. Following the station's opening on 1 October 1868, the MR constructed the Midland Grand Hotel on the station's façade, which has been widely praised for its architecture and is now a Grade I listed building along with the rest of the station.
In the late 1960s, plans were made to demolish St Pancras entirely and divert services for King's Cross and Euston, leading to fierce opposition. The complex underwent an £800 million refurbishment to become the terminal for the Channel Tunnel Rail Link/High-Speed 1/HS1 as part of an urban regeneration plan across East London, which was opened by Queen Elizabeth II in November 2007. A security-sealed terminal area was constructed for Eurostar services to mainland Europe via High Speed 1 and the Channel Tunnel, with platforms for domestic trains to the north and south-east of England. The restored station has 15 platforms, a shopping centre, and a coach facility. London St Pancras International is owned by HS1 Ltd and managed by Network Rail (High Speed), a subsidiary of Network Rail.