Crossness is a location in the London Borough of Bexley, close to the southern bank of the River Thames, to the east of Thamesmead, west of Belvedere and north-west of Erith. The place takes its name from Cross Ness, a specific promontory on the southern bank of the River Thames. In maritime terms, the tip of Cross Ness, in the past referred to as 'Leather Bottle Point', marks the boundary between Barking Reach and Halfway Reach. An unmanned lighthouse on Crossness is a navigational aid to shipping.