Historically, the Bedford Estate defined the boundary of Covent Garden, with Drury Lane to the east, the Strand to the south, St Martin's Lane to the west, and Long Acre to the north.[1] However, over time the area regarded as part of Covent Garden has expanded northwards past Long Acre to High Holborn.[26] Since 1971, with the creation of the Covent Garden Conservation Area which incorporated part of the area between St Martin's Lane and Charing Cross Road,[27] Charing Cross Road has sometimes been taken as its western boundary.[28][29] Long Acre is the main thoroughfare, running north-east from St Martin's Lane to Drury Lane.[30] Shelton Street, running parallel to the north of Long Acre, marks the London borough boundary between Camden and Westminster.[31]