Declared a monument in 1999. Situated on top of Tunnel in Cogmanskloof - 4km from Montagu towards Ashton.
1899 heralded the second Boer War and saw the construction of the English Fort above Cogmans Kloof. (Montagu and 2nd Boer War 11th October 1899 to 31st May 1902)
This was built by stonemason William Robertson at a site selected by Lieutenant Colonel Sidney, Commandant of the Royal Field Artillery.
The fort was garrisoned by a company of the Gordon Highlanders who were survivors of the Magersfontein battle. They were commanded by a Lieutenant Forbes.
They were camped on the original road construction site below Kalkoenkrans (Turkey Crag) the site which is now the parking area below the fort on the Montagu side.
Montagu had 4 small rectangular forts and a smaller circular one, all of which were instrumental in causing Commandant Gideon Scheepers and his Boer Commando of 300 men to avoid Montagu.
Strictly speaking, the well-known landmark at Cogman's Kloof is not a blockhouse but a construction of mortared stonework which shares some features with the blockhouses.
Perched high on a rock above the R62 road, three kilometres south of Montagu, it measures 9,3 x 3,8 m on the outside.
It has a simple entrance opening at the west end and 21 'waisted' loopholes formed in the masonry without steel plates. The loopholes are 700-800 mm above the concrete floor and the 400 mm thick stone walls reach a height of about two metres inside the building.
Inside the fort, near the south-east corner, is a roughly circular mortared stone platform (400 mm high), together with a drainage channel and hole at the base of the adjacent east wall, which seems to indicate the presence of a water tank and hence a roof.
It is not known how much of this building has been restored but one would expect the entrance to have been protected by a screen wall either inside or outside. Military History Journal Vol 10 No 6 - December 1997