The paper considers the methodological aspects of comprehensive archaeological and geological-geomorphological studies of fortifications dating back to the Early Iron Age – Early Middle Ages. The authors determined that settlements with the remains of earthworks and dwellings located on headland platforms in the condition they have retained until the present day are natural-anthropogenic complexes with three components: archaeological, geomorphological and geological, and should be studied using methods of the corresponding sciences. The history of the development of headland settlements is subdivided into the following three periods: pre-settlement, settlement and post-settlement (relic). The settlement period is in turn subdivided into three stages: the early stage associated with the carriers of the Ananyino cultural and historical area of the Early Iron Age (circa 9^th – 3^rd centuries B.C.); the middle period related to the construction activities of the population of the Piany Bor, Azelino and Mazunino cultures (2^nd century B.C. – 4^th century A.D.); and the late stage associated with the Imenkovo culture and the coexisting cultures of the Early Middle Ages (4^th – 7^th cc.). An analysis of information obtained as a result of studying the fortifications of promontory forts allows to conclude that the distinguished stages represent the historical stages of the development of fortifications across the Volga-Kama region.