Horne No 5 Slurry is a privately owned Earth dam located in Marianna Borough, Pennsylvania. Built in 1984, this dam stands at a height of 146 feet and has a length of 1460 feet, providing a storage capacity of 1817 acre-feet. The dam serves primarily for "Other" purposes and is regulated by the Pennsylvania Department of Environmental Protection.

With a drainage area of 0.12 square miles and a surface area of 28 acres, Horne No 5 Slurry poses a high hazard potential but is currently assessed to be in satisfactory condition. The last inspection conducted in December 2019 found the dam to be structurally sound. Although the dam is not owned or funded by any federal agency, it is subject to regulation and inspection by the Mine Safety and Health Administration.

Situated on TR HORN RUN in Washington County, Pennsylvania, Horne No 5 Slurry plays a crucial role in managing water resources in the region. Enthusiasts interested in water resource management and climate resilience will find this dam to be a significant component of the local infrastructure, ensuring the safety and security of the surrounding area in the face of potential hazards.