Grays Landing Lock And Dam
Grays Landing Lock And Dam is a gravity dam located in Greene County, Pennsylvania, built in 1995. It carries a Significant hazard potential classification.
About Grays Landing Lock And Dam
The primary purpose of Grays Landing Lock And Dam is navigation. The dam maintains water levels sufficient for boat and barge traffic, supporting commercial or recreational navigation on the waterway. The dam is owned by Usace - Pittsburgh District (federal). It impounds the Monongahela River near Grays Landing.
The dam stands 33 feet tall and stretches 680 feet across, creates a reservoir covering 796 acres, has a maximum storage capacity of 12,500 acre-feet, and collects water from a drainage area of 4,460 square miles. Completed in 1995, the structure is 31 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. An emergency action plan is in place for this dam. The most recent inspection on record was 05/12/2025.
At 33 feet, this dam is taller than 78% of dams nationwide.
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Location
| State | Pennsylvania |
| County | Greene |
| Nearest City | Grays Landing |
| River/Stream | Monongahela River |
| Coordinates | 39.82355, -79.92201 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 33 ft |
| Dam Length | 680 ft |
| Year Completed | 1995 (31 years old) |
Storage & Hydraulics
| NID Storage | 12,500 acre-ft |
| Max Storage | 12,500 acre-ft |
| Normal Storage | 12,500 acre-ft |
| Surface Area | 796 acres |
| Drainage Area | 4,460 sq mi |
| Max Discharge | 80,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - Pittsburgh District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not Available |
| Last Inspection | 05/12/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PA00124 |
| Federal ID | PA00124 |
| More Info | State Dam Safety Program |