Discover the Largest Dam in Pennsylvania (And What Lives in the Waters Behind It)

Written by Patrick Sather
Updated: August 3, 2023
© Rissing
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Key Points:

  • Raystown Dam is the tallest dam in Pennsylvania.
  • It is neatly tucked away in Huntingdon County.
  • The dam is positioned at the northern end of Raystown Lake, the largest lake in Pennsylvania.
The Raystown Dam is the tallest dam in Pennsylvania. It is 225 feet tall from base to top and 1,700 feet long. This makes it one of the largest dams in the eastern United States.

Situated in the Mid-Atlantic region of the United States, Pennsylvania supports numerous diverse ecosystems. Forests, wetlands, rivers, and lakes dot the state’s landscape. In fact, the state features over 83,000 miles of rivers and around 2,500 lakes and reservoirs. Many of these waterways are bordered by dams. These dams provide electricity, water storage, and flood control for the people of Pennsylvania and surrounding states. 

Most of Pennsylvania’s more than 1,500 named dams are relatively small, measuring just a few feet high and a few hundred feet long at most. However, a few of the dams in the state measure several hundred feet tall and thousands of feet long. But which dam in the state measures the largest?

In this article, you’ll discover the largest dam in Pennsylvania. We’ll also discuss the dam’s history, where it’s located, and what would happen if it broke. Discover the largest dam in Pennsylvania (and what lives in the waters behind it). 

Location of Raystown Dam

Raystown Lake is the largest lake located entirely in Pennsylvania.

©Christian Hinkle/

Raystown Dam is the tallest (although not necessarily the longest) dam located in Pennsylvania. Located in Huntingdon County, Raystown Dam lies at the northern end of Raystown Lake, the largest lake located entirely within Pennsylvania.

Situated within the Allegheny Mountains, Raystown Dam impounds the Raystown Branch Juniata River. Raystown Lake and Dam are located approximately 120 miles east of Pittsburgh, just off U.S. Route 22. Numerous small communities border the lake, including Entriken, Marklesburg, and Hesston, as well as several resorts. 

The History of Raystown Dam

Lake Raystown from the sky. Huntingdon county. The spillway at Raystown Dam.
Raystown Dam is the tallest dam located in Pennsylvania.


Prior to the arrival of European settlers, the area around the Raystown Dam was populated by bands of hunter-gatherers. These people eventually gave way to the Susquehannock Indians, whose territory stretched across much of the Susquehanna River and its tributaries. 

Both Raystown Dam and Raystown Lake get their name from Robert Ray, a trapper who camped in the area near Bedford around 1750. Ray’s camp eventually became known as Raystown, and the name is now shared by the lake, dam, and the river that feeds the lake. 

The current dam on Raystown Lake is not the original Raystown Dam. The beginnings of the original Raystown Dam date back to 1905. Supposedly, George Ernest and Warren Brown Simpson came up with the idea of damming the Raystown Branch Juniata River while on a fishing trip. Shortly thereafter, the 23rd governor of Pennsylvania, Samuel Pennypacker, signed the charter authorizing the construction of a hydroelectric dam, the first of its kind along that stretch of river. 

Upon receiving a charter to construct the dam, a group of locals formed the Raystown Water Power Company. This company financed the construction of the dam, which was finished in 1912. Over the years, ownership of the dam changed several times until the Pennsylvania Electric Company purchased the dam in 1946. You can still visit the old dam near mile marker 2 upstream of the current Raystown Dam. 

In 1936, the Juniata and Susquehannock River valleys both experienced major flooding. These floods led to calls for the construction of a new, larger dam on the Raystown Branch of the Juniata River. The 1962 Flood Control Act authorized the construction of the new dam, which was eventually completed in 1973.

Today, the Raystown Dam provides flood control, hydroelectric power, and recreational opportunities for the residents of Huntingdon County. Recreational facilities around Raystown Lake include 5 campgrounds, 10 boat launches, 10 picnic shelters, 2 marinas, an amphitheater, and 68.5 miles of trails. 

Size of Raystown Dam

The current Raystown Dam measures 225 feet tall from base to top, making it the tallest dam in Pennsylvania. At 1,700 feet long, its combined measurements make it one of the largest dams in the eastern United States. Only a handful of dams measure longer than the Raystown Dam in Pennsylvania. These include the Francis E. Walter Dam (3,000 feet), Adam T. Bower Dam (2,100 feet), and Kinzua Dam (1,897 feet). 

Wildlife in Raystown Lake

Esox masquinongy, muskellunge, muskie fish
Raystown Lake offers some of the best muskie fishing in the state of Pennsylvania.

©M Huston/

The 8,300-acre Raystown Lake supports a wide variety of animal species. Around the lake, you can find numerous birds, including grouse, turkeys, eagles, osprey, and warblers. There are many deer in the area, as well as beavers, river otters, minks, and raccoons

Raystown Lake features some of the best lake fishing in Pennsylvania. Within its waters, you can find numerous fish species, including:

  • Striped bass
  • Largemouth bass
  • Smallmouth bass
  • Lake trout
  • Muskellunge
  • Channel catfish
  • Walleye
  • Brown trout
  • Crappie
  • Bluegill
  • Yellow perch

What Would Happen if the Raystown Dam Ever Broke?

Dam failures can cause catastrophic disasters due to the sudden, violent release of large amounts of water. The amount of devastation varies depending on the degree of the break and the size of the dam. A minor break on a small dam does not pose as great of a threat as a major malfunction to a giant dam. Numerous reasons can cause a dam failure, including flooding, sabotage, structural failure of materials, piping or internal explosions, or inadequate upkeep. 

The U.S. Army Corps of Engineers maintains the National Inventory of Dams, a list of all known dams in the United States. In collaboration with FEMA, the agencies rate dams according to their hazard level from Low to High. 

Currently, the National Inventory of Dams lists Raystown Dam as a Moderate risk dam. A significant failure of the dam could release millions of gallons of water from Raystown Lake and cause massive flooding. This flooding could have devastating effects on both the people and economy of Huntingdon County. By some estimates, a major failure of the dam could greatly hinder the nearly $40,000,000 generated annually by tourism in the area. 

Additionally, a major break in the Raystown Dam would lead to large amounts of water entering nearby riverbeds and streams. This excess water would cause these waterways to overflow, damaging nearby flora and fauna. The added pressure could also lead to long-term changes in habitats due to the change in the structure of waterways and the surrounding landscape. These changes could have lasting impacts on wildlife in the area. 

Where Is Raystown Dam Located on a Map?

Raystown Dam is located in Huntingdon County at the northern end of Raystown Lake. Raystown Dam impounds the Raystown Branch Juniata River within the Allegheny Mountains. It is approximately 120 miles east of Pittsburgh, just off U.S. Route 22.

The Featured Image

Raystown Dam and Lake
Raystown Dam & Raystown Lake - Huntingdon, PA water woods
© Rissing

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