Countryside Landfill Dam, located in Grayslake, Illinois, is a private-owned structure designed by GEOSYNTECH to reduce flood risk in the area. Completed in 1997, this earth-type dam stands at a height of 13 feet and stretches 960 feet in length. It serves the primary purpose of flood risk reduction, with a storage capacity of 66 acre-feet and a maximum discharge capacity.

The dam is situated along the Avon-Fremont Drainage Ditch and is regulated by the Illinois Department of Natural Resources. With a low hazard potential and moderate risk assessment, the dam has an uncontrolled spillway with a width of 20 feet. Although the condition assessment is not available, the dam undergoes inspections every five years to ensure its structural integrity and safety.

While the Countryside Landfill Dam lacks certain emergency preparedness measures such as an Emergency Action Plan and updated contact information, it plays a crucial role in mitigating flooding in the region. Its strategic location and design make it a significant asset in managing water resources and climate resilience in Lake County, Illinois.