In 1975, the Northern City Line platforms were the site of the Moorgate tube crash – at the time, the worst peacetime accident in the history of the London Underground – in which 43 people were killed.

The public entrances from the street give access to all the train services at the station, there are three distinct levels.

These are disused following the closure of the Moorgate branch from Farringdon junction as part of the Thameslink Programme and are now used for storage.

Train services run via the East Coast Main Line to Welwyn Garden City, Hertford North and Stevenage.

[11] The station was opened as Moorgate Street by the Metropolitan Railway as the first eastwards extension from the original terminus at Farringdon.

Parliamentary power had been obtained to build a station at Moorgate in 1861, two years before the initial section, and it was completed on 23 December 1865.

Increased traffic from other companies, including goods traffic from the Great Northern Railway, led to the line between King's Cross and Moorgate being widened to four tracks; the route was called the City Widened Lines and included a new tunnel at Clerkenwell which was 16 feet (4.9 m) lower than the original.

[13] In 1874, director of the Metropolitan, Edward Watkin, described Moorgate Street as "your great terminus" and recommended a 100-bedroom hotel should be built on top of the station.

An act for the extension had been authorised in 1893 and included an eastern diversion of the original line underneath the Thames.

[18] The CS&LR line (taken over by the Underground Group in 1913) closed services between Moorgate and Euston on 9 August 1922 in order to widen tunnels to 11 feet 8+1⁄4 inches (3.56 m).

The section from Moorgate to Clapham Common was worked on during the night while daytime services remained running, but closed completely on 28 November 1923 following a roof collapse at Newington Causeway the day before.

A commemorative service ran on 6 June 1971 from Moorgate to the depot at Neasden, powered by a 0-6-0 tank locomotive.

[8] The closure was required in order to lengthen the platforms at Farringdon to take the longer trains, which could only be done southward in the direction of Moorgate as there was too steep a gradient to the north.

[34] Trains using the deep level Northern City Line platforms (9 and 10) are supplied with 750 V DC[35] current via the third rail, overseen by York Electrical Control Room.

[36] The shield was used to dig part of a very short planned extension south to Lothbury, quickly abandoned.

[37] The Metropolitan, Hammersmith & City and Circle lines serve the station between Barbican to the west and Liverpool Street to the east.