The Randstad is a roughly crescent- or arc-shaped conurbation in the Netherlands, that houses almost half the country's population. With a central-western location, it connects and comprises the Netherlands' four biggest cities, their suburbs, and many towns in between, that all grew and merged into each other. Among other things, it includes the Port of Rotterdam, the Port of Amsterdam, and Amsterdam Airport Schiphol. With a population of approximately 8.4 million people it is one of the largest metropolitan regions in Europe,[b] comparable in population size to the Rhine-Ruhr metropolitan region or the San Francisco Bay Area, and covers an area of approximately 11,372 km2 (4,391 sq mi).[a] The Randstad had a gross regional domestic product of €510 billion in 2022, making it the second most productive region in the European Union, only behind the Paris metropolitan area. It encompasses both the Amsterdam metropolitan area and Rotterdam–The Hague metropolitan area. It is part of the larger Blue Banana megalopolis.

A conurbation is a region comprising a number of metropolises, cities, large towns, and other urban areas which, through population growth and physical expansion, have merged to form one continuous urban or industrially developed area. In most cases, a conurbation is a polycentric urbanised area in which transportation has developed to link areas. They create a single urban labour market or travel to work area.