The Lion Harbour was Miletos’ most prominent harbour during antiquity. It can be envisaged as the heart of the Ionian metropolis in western Asia Minor. Originally situated in a bay of the “(I-)Karian Sea”, Miletos is now fully incorporated into the plain of the Maeander river, today’s
Büyük Menderes. In this article we combine results from historical andarchaeological research with those from palaeo-geography and geophysics. This geoarchaeological approach offers new insights into the dynamic evolution of the harbour basin from the time of the marine transgression in the early Bronze Age (c. 2500 BC), when the area formed part of an island, until its final siltation by the sediments of the river Maeander c. AD 1500.