IJmuiden is a port city in the Dutch province of North Holland. It is the main town in the municipality of Velsen which lies mainly to the south-east. Including its large sea locks, it straddles the mouth of the North Sea Canal to Amsterdam. To the south it abuts a large reserve of plant-covered dunes, the Zuid-Kennemerland National Park. The city is on the south bank; the north bank is otherwise a steel plant and Velsen-Noord.

Velsen is a municipality in the Netherlands, in the province of North Holland. It is located on both sides of the North Sea Canal.