To the Peshin valley the distance is about fro m., and from Peshin to India the three principal routes measure approximately as follows: by the Zhob valley to Dera Ismail Khan, 300 m.; by the Bori valley to Dera Ghazi Khan, 275 m.; by Quetta and the Bolan to Dadar, 125 m.; and by Chappar and Nari to Sibi, 120 m.
Two lines of railway now connect Quetta with Sind, the one known as the Harnai loop, the other as the Bolan or Mashkaf line.
BOLAN PASS, an important pass on the Baluch frontier, connecting Jacobabad and Sibi with Quetta, which has always occupied an important place in the history of British campaigns in Afghanistan.
Since the treaty of Gandamak, which was signed at the close of the first phase of the Afghan War in 1879, the Bolan route has been brought directly under British control, and it was selected for the first alignment of the Sind-Pishin railway from the plains to the plateau.
From Sibi the line runs south-west, skirting the hills to Rindli, and originally followed the course of the Bolan stream to its head on the plateau.
The destructive action of floods, however, led to the abandonment of this alignment, and the railway now follows the Mashkaf valley (which debouches into the plains close to Sibi), and is carried from near the head of the Mashkaf to a junction with the Bolan at Mach.
Of Sibi, the line starting in exactly the opposite direction to that of the Bolan and entering the hills at Nari.
The Harnai route, although longer, is the one adopted for all ordinary traffic, the Bolan loop being reserved for emergencies.
At the Khundilani gorge of the Bolan route conglomerate cliffs enclose the valley rising to a height of Boo ft., and at Sir-i-Bolan the passage between the limestone rocks hardly admits of three persons riding abreast.
The war began in March 1838, when the "Army of the Indus," amounting to 21,000 men, assembled in Upper Sind and advanced through the Bolan Pass under the command of Sir John Keane.
Sir Donald Stewart's force, marching up through Baluchistan by the Bolan Pass, entered Kandahar with little or no resistance; while another army passed through the Khyber Pass and took up positions at Jalalabad and other places on the direct road to Kabul.
An ad j acent opening, the Khyber Pass, the Kurram Pass to the south of it, the Gomal Pass near Dera Ismail Khan, the Tochi Pass between the two last-named, and the famous Bolan Pass still farther south, furnish the gateways between India and Afghanistan.
At this time both the Punjab and Sind were independent kingdoms. Sind was the less powerful of the two, and, therefore, a British army escorting Shah Shuja made its way by that route to enter Afghanistan through the Bolan Pass.
British armies advanced by three routes - the Khyber, the Kurram and the Bolan - and without much opposition occupied the inner entrances of the passes.
They include the whole of the Zhob and Chagai political agencies, the eastern portion of the Quetta tahsil and other tracts, among which may be mentioned the Bolan Pass, comprising 36,401 sq.
The point of this desert inlet receives the drainage of two local basins, the Bolan and the Nari.
The drainage of the Bolan and Nari finally disappears in the irrigated flats of the alluvial bay (Kach Gandava), which extends 130 m.
Advanced loop to include the Chaman railway terminus) on the west; reaching south through Shorarud to Nushki; including the basins of the Bolan and Nari as far as Sibi to the south-east; stretching out an arm to embrace the Thal Chotiali valley on the east, and following the main water-divide between the Zhob and Lora on the north, is called British Baluchistan.
The fortress of Kalat is situated about midway between the sources of the Bolan and the Mulla, near a small tributary of the Lora (the river of Pishin and Quetta), about 6800 ft.
Kalat is the " hub " or centre, from which radiate the Bolan, the Mulla and the southern Lora affluents; but the Lora drains also the Pishin valley on the north; the two systems uniting in Shorawak, to lose themselves in the desert and swamps to the west of Nushki, on the road to Seistan.
The population is largely nomadic. The fact that so many as 15,000 camels have been counted in the Bolan Pass during one month of the annual Brahui migration indicates the dimensions which the movement assumes.
In 1839, when the British army advanced through the Bolan Pass towards Afghanistan, the conduct of Mehrab Khan, the ruler of Baluchistan, was considered so treacherous and dangerous as to require " the exaction of retribution from that chieftain," and " the execution of such arrangements as would establish future security in that quarter."
Subsequent inquiries have, however, proved that the treachery towards the British was not on the part of Mehrab Khan, but on that of his vizier, Mahommed Hussein, and certain chiefs with whom he was in league, and at whose instigation the British convoys were plundered in their passage through Kach Gandava and in the Bolan Pass.
Since 1882 he has received Rs.25,000 as government rent for the Quetta district, besides Rs.30,000 in lieu of transit duties in the Bolan; this has been increased lately by Rs.9000 as already stated.
In March 1839 the British force under Sir Willoughby Cotton advanced through the Bolan Pass, and on the 26th of April it reached Kandahar.