The East End of London, often referred to within the London area simply as the East End, is the historic core of wider East London, east of the Roman and medieval walls of the City of London and north of the River Thames. It does not have universally accepted boundaries on its north and east sides, though the River Lea is sometimes seen as the eastern boundary. Parts of it may be regarded as lying within Central London (though that term too has no precise definition). The term "East of Aldgate Pump" is sometimes used as a synonym for the area.
https://en.wikipedia.org/wiki/East_End_of_London