Bilberry Reservoir, Austonley
- location: Austonley
- status: still exists
- category: reservoir
Together with Boshaw Whams and Holme Styes, the Bilberry Reservoir was one of three constructed by the Holme Reservoir Commissioners to store water for use by textile mills in the Holme Valley. Due to legal issues and non-payment of rates by the mill owners, the reservoirs were poorly maintained.
The embankment of the Bilberry Reservoir had been built on top of a small water spring which gradually eroded the puddle clay core, leading to the central section of the embankment slumping down below the level of the reservoir's waste pipe. Following a prolonged period of heavy rain, the reservoir began overflowing at around midnight on 5 February 1852. Around an hour later, the entire central section of the embankment collapsed and an estimated 86 million gallons of water poured down the Holme valley in a devastating flood that killed around 80 people.