The lands that lie within the boundaries of Hillside National Wildlife Refuge were transferred to the Fish & Wildlife Service by the Corps of Engineers in 1975. The Corps had purchased the land to complete the Hillside Floodway - Yazoo Basin Headwater Project. The project was designed to capture sediment and silt flowing off the loess hills, and prevent its entry into the Yazoo and Mississippi Rivers. The Corps then transferred the land to the Service "...for the conservation, maintenance and management of wildlife, resources thereof, and its habitat thereon."
Although the project was completed only 30 years ago, the Corps’ "Hillside Project" is nearing the 50 year-estimated capacity for silt and sediment capture. This is contributing to an evolving forest community, especially on the north end of the refuge, where bottomland forest species like oak and elm have been replaced by black willow and cottonwood. Due to the continued silt deposition, the forest is steadily changing as the silt moves in a southward direction and high quality hardwood forest habitat disappears in its wake. To help offset the loss, nearly 1,000 acres have been reforested, and several hundred more are being allowed to naturally regenerate.