Main Mill Dam
Main Mill Dam is a concrete dam located in Clinton County, New York, built in 1881. It carries a High hazard potential classification and has a poor condition assessment.
About Main Mill Dam
The primary purpose of Main Mill Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Imperial Industrial Park;nys Dec Division Of Fish And Wildlife (private). It impounds the Saranac River near Plattsburgh.
The dam stands 25 feet tall and stretches 715 feet across, creates a reservoir covering 84 acres, has a maximum storage capacity of 920 acre-feet, and collects water from a drainage area of 608 square miles. Completed in 1881, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 05/16/2024.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The New York dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | New York |
| County | Clinton |
| Nearest City | Plattsburgh |
| River/Stream | Saranac River |
| Coordinates | 44.68111, -73.47361 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 25 ft |
| Dam Height | 25 ft |
| Dam Length | 715 ft |
| Year Completed | 1881 (145 years old) |
Storage & Hydraulics
| NID Storage | 920 acre-ft |
| Max Storage | 920 acre-ft |
| Normal Storage | 830 acre-ft |
| Surface Area | 84 acres |
| Drainage Area | 608 sq mi |
| Max Discharge | 15,820 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | IMPERIAL INDUSTRIAL PARK;NYS DEC DIVISION OF FISH AND WILDLIFE |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 05/16/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NY00262 |
| Federal ID | NY00262 |
| More Info | State Dam Safety Program |