IJmuiden is a small 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.
It is 10 kilometres north northwest of Haarlem which is 18 kilometres due west of Amsterdam.
The port is a deepwater port suited to fully laden Panamax ships, and fourth port of the Netherlands.
The internal capitalization within IJmuiden is as IJ is a digraph in modern Dutch so in some typefaces recognised as a ligature which places it in one typed or handwritten space.