The valley of Laghman must always have been a populous valley. From the north the snow-capped peaks of Kafiristan look down upon it, and from among the forest-clad valleys at the foot of these peaks two important river systems take their rise, the Alingar and the Alishang, which, uniting, join the Kabul River in the flat plain, where villages now crowd in and dispute each acre of productive soil. It is difficult to reach the Laghman valley from the west. The defiles of the Kabul River are here impassable, but they can be turned by mountain routes, and Alexander's force, which included the Hyspaspists, who were comparatively lightly armed, with the archers, the "companion" cavalry and the lancers, was evidently picked for mountain warfare. The heavier brigades were with Hyphæstion who struck out by the straightest route for Peukelaotis, which has been identified with an ancient site about 17 miles to the north-east of Peshawur on the eastern bank of the Swat River, and was then the capital of the ancient Gandhara. We are told that Alexander's route was rugged and hilly, and lay along the course of the river called Khoes. Rugged and hilly it certainly was, but the Khoes presents a difficulty. He could not actually follow the course of the Kabul River (Kophen) from the Kabul plain because of the defiles, but he could have followed that river below Butkak to the western entrance of the Laghman valley where it unites with the Alingar, or Kao, River. It is impossible to admit that he reached the Kao River after crossing the Kohistan and Kafiristan, and then descended that river to its junction with the Kabul. No cavalry could have performed such a feat. Geographical conditions compel us to assume that he followed the Kabul River, which is sometimes called Kao above the junction of the Kao River.
It is far more impossible to identify the actual sites of Alexander's first military engagements than it is to say, for instance, at this period of history, where Cæsar landed in Great Britain, as we have no means of making exhaustive local inquiries; but subsequent history clearly indicates that his next step after settling the Laghman tribes was to push on to the valley of the Choaspes, or Kunar. It was in the Kunar valley that he found and defeated the chief of the Aspasians. The Kunar River is by far the most important of the northern tributaries of the Kabul. It rises under the Pamirs and is otherwise known as the Chitral River. The Kunar valley is amongst the most lovely of the many lovely valleys of Afghanistan. Flanked by the snowy-capped mountains of Kashmund on the west, and the long level water parting which divides it from Bajaor and the Panjkora drainage on the east, it appears, as one enters it from Jalalabad, to be hemmed in and constricted. The gates of it are indeed somewhat narrow, but it widens out northward, where the ridges of the lofty Kashmund tail off into low altitudes of sweeping foothills a few miles above the entrance, and here offer opportunity for an easy pass across the divide from the west into the valley. This is a link in the oldest and probably the best trodden route from Kabul to the Punjab, and it has no part with the Khaibar. It links together these northern valleys of Laghman, Kunar, and Lundai (_i.e._ the Panjkora and Swat united) by a road north of the Kabul, finally passing southwards into the plains chequered by the river network above Peshawur.