John H. Overton Lock and Dam is a gravity dam located in Rapides Parish, Louisiana, built in 1987. It carries a Significant hazard potential classification.
Dam profile
NID height · 104 ft104 ft tall and 914 ft long, taller than 98% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About John H. Overton Lock and Dam
The primary purpose of John H. Overton 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 - Vicksburg District (federal). It impounds the Red River near Simmesport.
The dam stands 104 feet tall and stretches 914 feet across, creates a reservoir covering 3,750 acres, has a maximum storage capacity of 67,500 acre-feet, and collects water from a drainage area of 67,458 square miles. Completed in 1987, the structure is 39 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 07/15/2025.
At 104 feet, this dam is taller than 98% of all dams in the United States.
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Location
| State | Louisiana |
| County | Rapides |
| Nearest City | Simmesport |
| River/Stream | Red River |
| Coordinates | 31.18703, -92.29283 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 104 ft |
| Dam Length | 914 ft |
| Year Completed | 1987 (39 years old) |
Storage & Hydraulics
| NID Storage | 67,500 acre-ft |
| Max Storage | 67,500 acre-ft |
| Normal Storage | 67,500 acre-ft |
| Surface Area | 3,750 acres |
| Drainage Area | 67,458 sq mi |
| Max Discharge | 255,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Navigation |
| Owner | USACE - Vicksburg District |
| Owner Type | Federal |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Last Inspection | 07/15/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | LA00581 |
| Federal ID | LA00581 |
| More Info | State Dam Safety Program |