The station was originally opened in November 1901 by the first deep-level tube railway, the City & South London Railway, as part of an extension of its line from Moorgate to Angel. The Northern City Line platforms were opened in February 1904 by the Great Northern & City Railway which built its tunnels to a larger diameter capable of accommodating main-line trains in the hope of carrying trains from its northern terminus at the Great Northern Railway's Finsbury Park station to Moorgate.
This is the closest underground station to Moorfields Eye Hospital. At the surface, the station is situated under the eastern edge of the busy Old Street roundabout, where Old Street crosses City Road. There is no ground-level station building, access being by ramps and stairs to a modern station entrance which is adjacent to a small shopping parade beneath the roundabout. The original ground-level buildings were removed when the roundabout was constructed. The station has toilets, but they are not open late into the evening. On the Northern line between Old Street and Angel stations is the disused tube station City Road.
Connections: National Rail.London Buses routes 21, 43, 55, 76, 135, 141, 205, 214, 243 and 271, night routes N35, N55, N76 and N205 and non-TFL route 812 serve the station.