Oostzaan is a municipality and a town in the Zaanstreek, Netherlands, in the province of North Holland. The municipality had a population of 9,689 in 2021. Oostzaan has a total area of 16.08 km2 (6.21 sq mi) of which 4.55 km2 (1.76 sq mi) is water.

North Holland is a province of the Netherlands in the northwestern part of the country. It is located on the North Sea, north of South Holland and Utrecht, and west of Friesland and Flevoland. As of January 2023, it had a population of about 2,952,000 and a total area of 4,092 km2 (1,580 sq mi), of which 1,429 km2 (552 sq mi) is water.