The main road to Warragamba used to veer left at this place & go through what is now Silverdale. Farnsworth Ave was not completed until well after the dam was completed. The trucks carrying supplies for the dam construction used to travel along Silverdale Rd to Warradale Rd then route to the dam site.
Busy intersection so muggles & local cachers passing by regularly,
You are looking for mint tin sized cache.