Lonaconing Reservoir
Lonaconing Reservoir is an earth dam located in Allegany County, Maryland, built in 1895. It carries a High hazard potential classification and has a poor condition assessment.
About Lonaconing Reservoir
The primary purpose of Lonaconing Reservoir is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Lonaconing Water Co (public utility). It impounds the Jackson Run near Lonaconing.
The dam stands 20 feet tall and stretches 185 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 22 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1895, 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. Notably, no emergency action plan is currently on file for this high-hazard dam. The most recent inspection on record was 11/19/2024.
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 Maryland 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 | Maryland |
| County | Allegany |
| Nearest City | Lonaconing |
| River/Stream | Jackson Run |
| Coordinates | 39.55210, -78.97428 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 185 ft |
| Year Completed | 1895 (131 years old) |
Storage & Hydraulics
| NID Storage | 22 acre-ft |
| Max Storage | 22 acre-ft |
| Normal Storage | 20 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 65 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Lonaconing Water Co |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 11/19/2024 |
| Emergency Action Plan | No |
Identifiers
| NID ID | MD00263 |
| Federal ID | MD00263 |
| More Info | State Dam Safety Program |