This paper presents the results of the work of the new field initiative launched by the British Museum at the Darband-i Rania pass in the Kurdistan Region of Iraq. The pass is located at the northeastern corner of Lake Dokan, where, though now subsumed into the lake, the Lower Zab flows from the Peshdar into the Rania Plain. It is a strategic location on a major route from Mesopotamia into Iran, and control of both the road and the river must always have been important. The aim of the work, which commenced in autumn of 2016, is to explore a cluster of sites that commanded the pass, with a particular focus on the first millennium b.c. Excavation is being carried out principally at two sites: Qalatga Darband, a large fortified site at the western end of the pass, and Usu Aska, a fort inside the pass itself. The occupations of these two sites are predominantly Parthian and Assyrian respectively. Smaller operations have also been carried out at Murad Rasu, a multi-period site situated on a headland across the waters on the southern shore of Lake Dokan. The results have included the discovery at Qalatga Darband of a monumental complex built of stone and roofed with terracotta roof tiles containing the smashed remains of Hellenistic statuary. Other features indicative of Hellenistic material culture are Mediterranean-type oil-presses and Corinthian column bases and capitals. At Usu Aska remains are being uncovered of an Assyrian fortification of massive proportions.