River Tyburn, London

The River Tyburn is a river in London, which runs underground from South Hampstead through St James's Park to meet the River Thames by Whitehall Stairs (near Downing Street and Thorney Street, between Millbank Tower and Thames House). It is not to be confused with the Tyburn Brook which is a tributary of the River Westbourne that is the next Thames tributary to the west on the north bank.

Before it was culverted, the Tyburn rose from the confluence of two tributary streams from the hills of South Hampstead. Its main source is the Shepherd's Well near Fitzjohn's Avenue in Hampstead. Between St James's Park and Buckingham Palace the waters divided to create two distributaries, creating Thorney Island on which Westminster Abbey was built. Enclosed by concrete, bricks, parks and roads the Tyburn flows through underground conduits for its entire length, including one underneath Buckingham Palace and its course has been used for local sewers which connect to the London sewerage system.Marylebone Lane (W1), which defies the grid pattern of streets, follows the course of the Tyburn on what was its left bank through Marylebone village.

From its source at the Shepherd's Well near Fitzjohns Avenue in Hampstead it follows Scholar's Pond Sewer south along Fitzjohns Avenue through South Hampstead (Swiss Cottage) under Avenue Road to Regent's Park. To enter the park's perimeter the Tyburn is carried in an aqueduct over the Regent's Canal then culverted.

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