The North Entrance to the Western Heights was situated at a narrow point of the ridge towards the north-eastern end of the fortress, where the North Military Road completed its more moderate ascent from Dover town. The earliest phase of works on this entrance dates to the Napoleonic period, but further work on the North Entrance to complete and modernise it began in in March 1860 and it was finished by February 1864. This created a more elaborate defensive scheme and perhaps reflects a greater concern with a potential assault from the north. A tunnel was constructed as part of these 1860’s works between the inner and the outer entrance. (location accurate to the nearest 1m based on available information)