Since industrialisation began in the 19th century, some ports have been moving away from the cities that once hosted them. That separation was only possible if land was available where new port basins, industries, and other infrastructure could be constructed and where port activities could prosper without being restricted by urban functions. The port of Rotterdam represents an extreme example of port-city separation. This chapter shows how the port of Rotterdam transformed from a staple port into a transit port. Port activities moved towards the North Sea in four steps that were related to technological, institutional, and trade pattern changes and changes in port-city relations. Such transitions highlight the close relationships between trade patterns, technological innovations and changing governance patterns. Each expansion required close collaboration between business leaders and the municipality, because administrative borders needed to be expanded and infrastructure constructed. The growth also created friction among the various stakeholders in the region. The merchants of the staple markets protected their trades and traditions, whereas the harbour barons that benefited most from the high-volume transshipment of bulk commodities pushed the expansion of the port. To illustrate these steps in the separation of port and city, the chapter takes the case of petroleum as a key example. While beneficial for the economic development of the port-and to some degree the city-the separation of port and city has led to a loss of connection between port and city institutions. The chapter concludes by briefly examining the challenges and opportunities of port and city separation in terms of economic, spatial and cultural development.