Harrestrup Å is an approximately 20 km long stream through the western suburbs of Copenhagen, Denmark.

It rises at Harrestrup Mose in Vestskoven woodland on the border between Albertslund and Ballerup and flows through Damhus Lake and several parks on its way to the Øresund at Kalvebod Beach in Valby Park.

The stream rises at Mønterne/Herstedhøje just south of Harrestrup Mose and this first, short section is called Rogrøften.

[1] Harrestrup Mose is also fed by Ballerup-Skovlunde Skolerende from the north and Bymoserenden from the south.

The project is a collaboration between nine municipalities and the HOFOR utility company.