Ludgate Hill is a hill in the City of London, near the old Ludgate, a gate to the City that was taken down, with its attached gaol, in 1780. It is the site of St. Paul's Cathedral, traditionally said to have been the site of a Roman temple of the goddess Diana. It is one of the three ancient hills of London, the others being Tower Hill and Cornhill. The highest point is just north of St. Paul's, at 17.6 metres (58 ft) above sea level.
Ludgate Hill is also the name of a street which runs between St. Paul's Churchyard and Ludgate Circus (built in 1864), from where it becomes Fleet Street. It was formerly a much narrower street called Ludgate Street.
Many small alleys on Ludgate Hill were swept away in the late 1860s to build Ludgate Hill railway station between Water Lane and New Bridge Street, a station of the London, Chatham and Dover Railway. It was closed in 1923 and the railway bridge and viaduct between Holborn Viaduct and Blackfriars stations was demolished in 1990 to enable the construction of the City Thameslink railway station in a tunnel. This also involved the regrading of the slope of Ludgate Hill at the junction.
There is a blue plaque near the bottom of the hill with these words: "In a house near this site was published in 1702 The Daily Courant first London daily newspaper".
About halfway up Ludgate Hill is the church of St. Martin, Ludgate, once physically joined to the Ludgate.
Paternoster Square, home of the since 2004, lies on the hill, immediately to the north of St. Paul's Cathedral.