The settlement structure in Bactria during the early Iron Age and the Hellenistic period has undergone considerable changes. Paradoxically, it appears that in some early stages of development - in the period of Yaz I culture in particular - some parts of Bactria prove to be more densely and more intensively settled than in the period after the fall of the Achaemenid Empire, when Bactria was ruled by Greeks.
Czech-Uzbek expedition mapped the area of the Sherabad oasis, north-western Bactria, where we can prove eight sites of the Hellenistic period, compared to ten - and mostly different - early Iron Age sites. Interesting situation has been attested in the nearby piedmont steppe belt: there is evidence of significant amount of the Yaz I and Yaz II settlements, fewer Achaemenid and only two Hellenistic sites.
The placement of towns and fortresses in the wider area of northern Bactria Also varies considerably as well. The Achaemenid settlements on the banks of the Amu Darya are rare, while in Hellenistic period this artery was guarded by new forts (e.g.
Kamyrtepa, Termez). At the same time, in Hellenistic period new forts were constructed to reinforce the natural barrier of the mountains in the piedmonts of Kugitang and Baysuntau, such as newly excavated sites of Uzundara, Kurganzol, and already famous Iron-gate fort.
In any case, the settlement distribution and density during both Achaemenid and Hellenistic periods shows clearly an unexploited potential of the local landscape. The settlement structure of following Kushan period in its turn seems to be considerably more intensive and extensive, not to mention construction of sophisticated irrigation system.