New Mills
New Mills is a masonry dam located in Kennebec County, Maine, built in 1885. It carries a High hazard potential classification and has a fair condition assessment.
About New Mills
The primary purpose of New Mills 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 Gardiner;litchfield;richmond (local government). It impounds the Cobbosseecontee near Gardiner.
The dam stands 22 feet tall and stretches 200 feet across, creates a reservoir covering 856 acres, has a maximum storage capacity of 4,650 acre-feet, and collects water from a drainage area of 217 square miles. Completed in 1885, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 07/09/2025.
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 Maine 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 | Maine |
| County | Kennebec |
| Nearest City | Gardiner |
| River/Stream | Cobbosseecontee |
| Coordinates | 44.22000, -69.79000 |
Physical Characteristics
| Dam Type | Masonry |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 200 ft |
| Year Completed | 1885 (141 years old) |
Storage & Hydraulics
| NID Storage | 4,650 acre-ft |
| Max Storage | 4,650 acre-ft |
| Normal Storage | 2,850 acre-ft |
| Surface Area | 856 acres |
| Drainage Area | 217 sq mi |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Gardiner;Litchfield;Richmond |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 07/09/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | ME00095 |
| Federal ID | ME00095 |
| More Info | State Dam Safety Program |