Harlan County Dam is a gravity dam located in Harlan County, Nebraska, built in 1952. It carries a High hazard potential classification.
Dam profile
NID height · 107 ft107 ft tall and 11,827 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 Harlan County Dam
The primary purpose of Harlan County Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by USACE - Kansas City District (federal). It impounds the Republican near Naponee.
The dam stands 107 feet tall and stretches 11,827 feet across, creates a reservoir covering 13,600 acres, has a maximum storage capacity of 825,700 acre-feet, and collects water from a drainage area of 7,636 square miles. Completed in 1952, the structure is well into its service life at over 50 years 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. An emergency action plan is in place for this dam. The most recent inspection on record was 06/12/2025.
At 107 feet, this dam is taller than 98% of all dams in the United States.
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 Nebraska 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 | Nebraska |
| County | Harlan |
| Nearest City | Naponee |
| River/Stream | Republican |
| Coordinates | 40.06876, -99.21125 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 107 ft |
| Dam Height | 107 ft |
| Dam Length | 11,827 ft |
| Year Completed | 1952 (74 years old) |
Storage & Hydraulics
| NID Storage | 825,700 acre-ft |
| Max Storage | 825,700 acre-ft |
| Normal Storage | 327,600 acre-ft |
| Surface Area | 13,600 acres |
| Drainage Area | 7,636 sq mi |
| Max Discharge | 485,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - Kansas City District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Last Inspection | 06/12/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NE01066 |
| Federal ID | NE01066 |
| More Info | State Dam Safety Program |