Squam Lake
Squam Lake is a concrete dam located in Grafton County, New Hampshire, built in 1856. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Squam Lake
The primary purpose of Squam Lake is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is state-owned. It impounds the Squam River near Ashland.
The dam stands 17 feet tall and stretches 200 feet across, creates a reservoir covering 7,173 acres, has a maximum storage capacity of 39,600 acre-feet, and collects water from a drainage area of 58 square miles. Completed in 1856, the structure is one of the older dams in the region, with over a century and a half of service.
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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 05/14/2025.
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 New Hampshire 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 Hampshire |
| County | Grafton |
| Nearest City | Ashland |
| River/Stream | Squam River |
| Coordinates | 43.70559, -71.62942 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 17 ft |
| Dam Height | 17 ft |
| Dam Length | 200 ft |
| Year Completed | 1856 (170 years old) |
Storage & Hydraulics
| NID Storage | 39,600 acre-ft |
| Max Storage | 39,600 acre-ft |
| Normal Storage | 39,600 acre-ft |
| Surface Area | 7,173 acres |
| Drainage Area | 58 sq mi |
| Max Discharge | 1,470 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/14/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00059 |
| Federal ID | NH00059 |
| More Info | State Dam Safety Program |