The western entrance to the Essex Hill munitions storage tunnel (Ho2) is located at the bottom of a quarry face at the back of a wooded quarry to the north of Essex Castle. The tunnel is about 400 yards in length and runs in a semi circle to the partially blocked and overgrown eastern entrance. The tunnel is unlined throughout as are three short munitions storage chambers close to the middle of the tunnel.
There is also a short section of 60cm tramway in place towards the centre of the tunnel. The tunnel is dry and safe to enter with a small roof fall in the centre that is easily passed. The chassis of a railway truck is buried beneath a minor roof fall at the eastern end.