The River Tyburn was a stream in London, England. Its main successor sewers emulate its main courses, but it resembled the Colne in its county of Middlesex in that it had many distributaries. It ran from South Hampstead, through Marylebone, Mayfair, St James's parish/district and Green Park to meet the tidal Thames at four sites, grouped into pairs. These pairs were near Whitehall Stairs, and by Thorney Street, between Millbank Tower and Thames House. Its much smaller cousin, the Tyburn Brook, was a tributary of the Westbourne and the next Thames tributary.