| Laurel Run Dam | |
|---|---|
.jpg) Laurel Run dam failure in 1977 | |
  Location of Laurel Run Dam in Pennsylvania | |
| Location | West Taylor Township, Cambria County, near Johnstown, Pennsylvania, United States |
| Coordinates | 40°23′03″N 78°54′56″W / 40.38417°N 78.91556°W |
| Construction began | 1915 |
| Opening date | 1919 |
| Demolition date | July 20, 1977 |
| Owner(s) | Johnstown Water Authority |
| Dam and spillways | |
| Type of dam | Earthen embankment |
| Impounds | Laurel Run Creek |
| Height | 42 feet (13 m) |
| Reservoir | |
| Creates | Laurel Run Reservoir |
| Total capacity | 101,000,000 US gallons (380,000 m3) |
| Catchment area | 18 square miles (47 km2) |
| Surface area | 22 acres (89,000 m2) |
The Laurel Run Dam, also known as Laurel Run Dam No. 2, was an earthen embankment dam that failed during the Johnstown Flood of 1977. It had the largest reservoir of seven dams to fail between July 19 and 20, 1977 and caused the most fatalities of the two that did. The dam failed in the early morning of July 20 after period of heavy rain, causing 101 million US gallons (380,000 m3) of water to flood downstream Tanneryville, killing 40 people.