In Kalat-e Naderi only two main approaches provide access to the interior, one called Arḡavān (Arḡun) to the southwest, and one called Naftā to the northeast. They are linked by the presence of a superimposed river, flowing northeast, which crosses the syncline from one side to the other and has carved a valley through the heart of the fortress, 350 to 500 meters deep, and of varying width, in the soft rock underlying the limestone. These geological conditions yield good arable soil between the grassy plains of the banks.
Three secondary approaches, to the southeast, west, and northeast, accommodate very narrow, difficult mule paths, negotiable only in single file. There are a few tracks for shepherds and goats, which are nearly impossible to traverse in some places without resorting to using hands.
The name of Nāder Shah has remained inseparable from this place ever since, but after his death it rapidly lost any political or even major military function, becoming simply the seat of the chief of the local tribe (Jalāyer), who was entrusted with the administration of the district as well as its defense against the Turkmens. Western scholars and travelers had been aware of the existence of the place and its difficulty of access since the beginning of the 19th century, but at that time they were unable to provide an exact description (Kinneir, pp. 176–77). J. B. Fraser, even though he had traveled in the Khorasan, spoke of it only by hearsay (Fraser, Appendix B, pp. 53–55). The very precise and detailed description of Kalāt-e Nāderi given by the Greek merchant Basile Vatatzes, after his visit in the time of Nāder Shah in 1728, remained unpublished and was not edited until much later (ed. E. Legrand, 1886).
It was not until the time of Nāṣer-al-Din Shah and the advent of modernization and centralization, when the ravages of the periodic incursions of the Turkmen became a matter of public and governmental concern, that the location was once again recognized as justifying special attention and requiring the stationing of a permanent garrison. Moreover, during the last decades of the 19th century, a more accurate description of the area had begun to emerge from the observations of the British officers and explorers drawn in some number to the region by the trans-Caucasian advance of the Russians and the gradual subjection by them of the Turkmens in the 1880s.