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Aqueducts, inclines and mules: How the Pennsylvania Canal changed the Commonwealth

Archives & Special Collections
University of Pittsburgh Library System
An 1833 map of the state of Pennsylvania, which includes the canal system stretching across the commonwealth. The canals are depicted in blue and railroads are in a dark purple.

Before highways and railroads crisscrossed the commonwealth, a series of linked waterways and inclined planes brought people and goods across the state. The Pennsylvania Canal was a significant engineering achievement when it was constructed in 1826.

Good Question! asker Michael Gragan said he took a Pittsburgh history class and remembers seeing an aqueduct spanning the Allegheny River in an old photograph.

“Apparently it was part of the canal system that bore water-born commerce above the river,” Gragan said. “I remember thinking, ‘That’s kind of fascinating that it wouldn’t be on the river, actually above it.’”

Listener Rob Hallet tried to picture the system coming down the river before railroads existed here.

“To think that there was a canal at one time is pretty amazing,” Hallett said. 

Credit Katie Blackley / 90.5 WESA
90.5 WESA
The Pennsylvania Canal wove through what's now the North Shore and came out near the current site of PNC Park. The aqueduct into downtown was near where the Ft. Wayne Railroad Bridge is now, which is the steel truss bridge in the far right of the picture, between the Rachel Carson (9th Street) and David McCullough (16th Street) bridges.

Commercial competition across the commonwealth

In 1825, the Erie Canal linked New York City to Niagara Falls and enhanced trade opportunities in the eastern United States. Watching its success, Pennsylvania merchants became envious. Dave Wright with the Pennsylvania Canal Society, an organization that preserves the system’s history, said commonwealth businesses and lawmakers didn’t want to be left out.

“They said, “Well, we’ve got to do something about this,’” Wright said. “So they sent an architect … to try and take notes and to observe the technology that had been developed.”

Credit Archives & Special Collections / University of Pittsburgh Library System
University of Pittsburgh Library System
An 1835 map of downtown Pittsburgh and Allegheny City depicts the Pennsylvania Canal system running through what's now the North Shore and into the Allegheny River. It also shows the aqueduct that went from the North Side to where 11th Street is now near the convention center.

Pennsylvania’s topography is different from New York’s, so engineers were challenged to design a system that could traverse the state’s mountain ranges and waterways. Locks, dams, aqueducts and viaducts were constructed from Philadelphia to Pittsburgh and inclined planes, similar to the Duquesne and Monongahela that still exist today, helped boats climb over the Allegheny Mountains.

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 The section that connected to Pittsburgh is referred to as the Western Division. It began in Johnstown, where it followed the Conemaugh River to Saltsburg. There it joined the Kiskiminetas River until it reached Freeport, where it meets the Allegheny River.

As it made its way parallel to the Allegheny River, the canal came into Pittsburgh along the North Side. Wright said the route along the eastern part of the city didn’t work as well.

“The hills in Plum Borough were too close to the edge of the river and there wasn’t enough room to build the channel for a canal next to the river,” Wright said. 

Credit Archives & Special Collections / University of Pittsburgh Library System
University of Pittsburgh Library System
This Aug. 14, 1911 photo shows a stone arch over the old canal and wall for a sewer near Try Way near Second Avenue.

The canal followed what’s now South Canal Street and the railroad tracks that run parallel to Route 28. It snaked through the North Shore and connected to the Allegheny River at a pier where PNC Park is today.

Hoping for an increase in commercial traffic, Pittsburghers lobbied the Pennsylvania legislature to fund a branch into the city. Architect John A. Roebling was chosen in 1844 to design an aqueduct across the Allegheny River. 

The navigable aqueduct was about 15 feet wide and was located between Hope Street on the North Side and 11th Street Downtown. 

“There were canal basins on each side for the boats to load and unload their goods,” Wright said. 

Credit Courtesy Saltsburg Historical Society
A map of Saltsburgh (when it still had the "h" in its name), Pa. The Pennsylvania Canal can be seen nearly following the route of the Kiskiminetas and Conemaugh rivers. The community was heavily shaped by the canal's presence.

  The canal then continued along Grant Street into an underground tunnel where the U.S. Steel Building is now located. It emerged again near the Manor Building (next to the Allegheny County Courthouse) and stopped at the Monongahela River. 

How it changed Pennsylvania

The Pennsylvania Canal played a significant role in the development of towns along its path throughout the state. Jack Maguire was born and raised in Saltsburg, Pa., a town of about 800 people a little more than 30 miles east of Pittsburgh. The community got its name from the discovery of salt and subsequent manufacturing of the mineral, but it really took off when the canal system was constructed there.

“With the beginning of the canal, the population in Saltsburg just blossomed,” Maguire said. “A lot of people came to town to be part of the two canal building yards.”

Carpenters and other merchants moved to be close to the canal so they could easily transport their products around the state. At the height of its operation, Maguire said the canal would see boats approximately every 15 minutes. 

When the canal was completed, it cut travel time from Philadelphia to Pittsburgh from three weeks to three-to-five days. The country was experiencing the Industrial Revolution, and southwestern Pennsylvania was rapidly increasing its manufacturing capacity. Pittsburgh was ramping up its coal and iron production, and neighboring cities were rich with products like natural gas and lumber. The city’s population quadrupled during the canal’s decades of operation.

Credit Engineering Pittsburgh / ASCE Pittsburgh Section 100th anniversary Publication Committee
ASCE Pittsburgh Section 100th anniversary Publication Committee

How a canal works

Canals are man-made waterways, similar to rivers, that are typically connected by lock and dam systems. The navigation systems are not built directly on rivers, however, due to their variability.

“If you used a river, in the spring when you have the thaws, the water would be too fast. In the fall, if there’s a drought, not enough water,” Maguire said. “By having an independent system, you’d avoid those problems.”

Credit Katie Blackley / 90.5 WESA
90.5 WESA
Jack Maguire with the Saltsburg Historical Society points to where the Pennsylvania Canal once came through Saltsburg. The site has been paved over and now has a curve in the concrete to indicate the waterway's history.

This was one of the reasons the aqueduct across the Allegheny River was constructed--it would make travel across the water more manageable and safer for passengers and commerce.

Still, rivers were usually the most logical path to follow, since the land around them was often flat. Workers dug ditches and used clay from the area to make a one-foot water-tight layer. The water that supplied the canal wasn’t from the river, but from a series of dams built specifically for that purpose. Maguire said a memorable local example is the South Fork Dam, built as a reservoir for the canal in Johnstown, Pa.

The locks and dams leveled out the water, like a series of steps. Boats enter the lock and the amount of water was either increased or decreased, depending on the direction, then when the level is right, the lock opened and the boat continued on.

Towpaths were built alongside the canals so horses or mules could pull boats through different parts of the system. 

The canal system wasn’t navigable all year long, though, due to freezing temperatures in the winter. When the railroad system was constructed, the canal ceased to be useful.

“Railroads don’t freeze,” said Maguire.

Credit Carnegie Library Archives
The Penn Incline and the Penn Incline Resort c. 1889 in what's now Pittsburgh's Strip District. The inclined planes in the city would have been similar to those used in the Pennsylvania Canal system.

  Inclined planes

One of the most significant engineering achievements that came out of the canal was the use of inclined planes. The Allegheny Portage Railroad was the first railroad built through the Allegheny Mountains and connected the Pennsylvania Canal system by hauling boats and barges up the hill using steam engines. Like the Monongahela and Duquesne inclines, the engines used a counterweight system.

“It’s an ingenious system that they came up with,” Maguire said. But with the hefty weight of many of the barges passing through the system, Maguire said engineers figured out how to cut the boats into thirds, make them watertight, and then reassemble them at the end of the ride.

“It was a creative way to handle that problem with the weight,” Maguire said.


Remnants of the canal

Residents of Saltsburg host a Canal Days celebration each year. The community has rebuilt the path the system took, often including informational signs for walkers and cyclists.

In Apollo, Pa. along the Roaring Run Trail, there are remnants of the canal lock. Many of the rail lines at the Portage Railroad National Historic site have been preserved or recreated. In Beaver Creek State Park, Ohio, about 45 miles northwest of Pittsburgh, there are remnants of the canal extension from the Pittsburgh region into Ohio. 

In Pittsburgh, stones from the Pittsburgh Weigh Lock and Lift No. 4 on the North Side were discovered when crews constructed I-279. Preservation Pittsburgh Director Dana Cress said her organization is in talks with local architects and engineers to create a reinterpretation of the massive stones.

“We found out that the canal stones happen to be in storage at PennDOT,” Cress said. “We’re working with community partners … to find a location and design to allow the public to interact with them.”

A historic marker commemorating the canal can be found near Union Station at Liberty and Grant streets.


Katie Blackley is a digital editor/producer for 90.5 WESA and 91.3 WYEP, where she writes, edits and generates both web and on-air content for features and daily broadcast. She's the producer and host of our Good Question! series and podcast. She also covers history and the LGBTQ community.