The Zaan (Dutch pronunciation: [zaːn] ⓘ) is a small river in the province of North Holland in the northwestern Netherlands and the name of a district through which it runs.

The river was originally a side arm of the IJ bay and travels 13.5 kilometers (8½ miles) through the municipalities of Zaanstad ("Zaan City") and Wormerland north of Amsterdam, from West-Knollendam in the north to Zaandam in the south, where it empties into the IJ.

During the Dutch Golden Age in the 17th century, the Zaan district was dotted with windmills with a variety of functions and it is often considered to be one of the world's first industrialized areas.

By the mid-17th century, approximately 900 windmills could be found along the river, some of them still preserved, particularly in the Zaanse Schans neighbourhood of Zaandam, near Zaandijk.

"[2] Monet returned to the Zaan district to paint during visits to the Netherlands in following years[citation needed].