The present study focusses on two relatively neglected areas. Their only partially published heritage inventory formed the basis for studies in settlement and coastal archaeology, completed by the publication of small-scale excavations, landscape history, archaeobotany, and archaeozoology. The analysis as well as chronological, social, and functional classification of finds and features casts new light on settlement processes at the edge of the sea. In contrast to received wisdom, settlements started to be built in the Migration Period. At first, there were settlements on level ground, later on the formation of first terps is evident. Village terps in the still undiked marshes were complemented by numerous single-farm terps, often arranged in lines, in the course of High and Late Medieval dike construction and settlement expansion. Thus, the long-known settlement areas on the geests of the islands of Sylt, Föhr, and Amrum and on Eiderstedt can now be supplemented by two more areas which considerably broaden our understanding of regional settlement processes, maritime trade networks, contacts between the islands and the mainland, and landscape changes caused by humans and the sea.