The street is the main link between the two cities of Westminster and London . It run eastward from Trafalgar Square , parallel to the River Thames , to Temple Bar which is the boundary between the two city districts ; the road ahead being Fleet Street . Traffic travelling eastbound follow a short crescent around Aldwych , connected at both ends to the Strand . The road mark the southern boundary of the Covent Garden district and form part of the Northbank business improvement district .