The cantonment was in the form of a parallelogram, with the Bimaru heights running along, and protecting, the northern side.

Between this range and the hills, which form the southern boundary of Kohistan, lay a lake, or rather _jhil_, a barrier between which and the commanding Bimaru ridge no enemy would dare to advance.
The massive wall on the south and west faces was twenty feet high, covered at a distance of thirty feet by a lower wall fifteen feet high; the southern wall was pierced at intervals of about 700 yards by gateways, three in number, protected by lofty circular bastions, and between these and at the four corners were a series of low bastions which gave an admirable flanking fire.

The wall on the western flank was of similar construction, but had been considerably damaged at the northern end, evidently by an explosion of gunpowder.
The weak part of our defence was on the eastern face, where the wall, which had never been completed, was only seven feet high, and did not extend for more than 700 yards from the south-east corner; the line then ran to the north-west, and, skirting the village of Bimaru, ended at the foot of the ridge.
From this description it will be seen that, though the perimeter[1] of Sherpur was rather too large for a force of 7,000 effective men to defend, its powers of resistance, both natural and artificial, were considerable.

It was absolutely necessary to hold the Bimaru ridge for its entire length; to have given up any part of it would have been to repeat the mistake which proved so disastrous to Elphinstone's army in 1841.

In fact, the Bimaru heights were at once the strength and the weakness of the position.