Hillsborough Estates is a rural residential development located near Oakdale in Stanislaus County, California. Phase 1 was 16 acres and consisted of 23 residential lots. Phase 2 was much larger encompassing 46 acres and 66 lots. The project included design and construction of backbone infrastructure including streets, storm drain outfall to the Stanislaus River, and a community domestic water system (managed by the Oakdale Irrigation District). Wastewater is handled by individual septic systems.