The Patowmack Canal

Lock 1 of the Patowmack Canal
Lock 1

NPS Photo

Few ventures were dearer to George Washington than his plan to make the Potomac River navigable as far as the Ohio River Valley. In the uncertain period after the Revolutionary War, Washington believed that better transportation and trade would draw lands west of the Allegheny Mountains into the United States and "...bind those people to us by a chain which never can be broken."

"The way," Washington wrote, "is easy and dictated by our clearest interest. It is to open a wide door, and make a smooth way for the produce of that Country to pass to our Markets ...."

As a waterway west the Potomac River could be that "door." It was the shortest route between tidewater, with access to East Coast and trans-Atlantic trade, and the headwaters of the Ohio River, with access to the western frontier. But both political and physical obstacles had to be overcome.

The Patowmack Company

Opening the Potomac required cooperation of Virginia and Maryland, which bordered the river. In 1784, Washington convinced the states' assemblies to establish a company to improve the Potomac between its headwaters near Cumberland, Md., and tidewater at Georgetown. The Patowmack Company, organized May 17, 1785, drew directors and subscribers from both states.

The office of president, Washington wrote in his diary, "fell upon me." He presided over the project until he became the nation's chief executive.

The Canal and the Constitution

Delegates from Virginia and Maryland, meeting at Washington's home in 1785, drew up the Mount Vernon Compact, providing for free trade on the river. Virginia and Maryland legislators ratified the compact and then invited all 13 states to send delegates to a convention in Annapolis in 1786 "to consider how far a uniform system in their commercial regulations may be necessary to their common interest."

The Annapolis Convention led to a general meeting in Philadelphia the following May. Thus, George Washington's lobbying for interstate cooperation on the Potomac helped prepare the way for the Constitutional Convention of 1787.

Patomack Canal company logo
The Patowmack Company Logo

NPS Image

Construction of the Canal
The Patowmack Company began construction of the five part skirting canal system in 1785, and continued for 17 years. It fully opened to traffic a year after construction finished, in 1802. The endeavor of the Patowmack Company ultimately went bankrupt and transferred its charter to the C&O Canal in 1828. However, a shifted perspective in studying this canal’s history as the first evolutionary stage of America's transportation industry would shine a light of achievement on the Patowmack Company's ingenuity.

The upriver portions of the canal system were constructed first and were built with mixed workforces of mainly unskilled laborers, indentured servants, and minimal enslaved laborers. That would change in 1792, one year after work began at Little Falls, there were over 100 men digging the canal bypass; among them still only 10 listed as enslaved labors. At the November 05, 1792 meeting, the Patowmack Company board authorized the renting up to 200 enslaved laborers at a cost of $60/year. However, by January 1794 they had only been able to rent 60 enslaved laborers for the coming year. Additionally, it is well documented that by the time construction had begun at Great Falls and Little Falls the Patowmack Company was facing constant financial problems. Indentured servants would regularly flee work sites before their indenture-mortgages were paid; this compounded the losses to the company. For this reason the Patowmack Company’s board members continued authorizing supervisors to rent many numbers of enslaved laborers from neighboring plantations to complete the construction of the downstream canals closest to the new capital city.

Getting around the Great Falls
Three upriver sections of the canal did not require locks to be built, but instead the river was dredged and boulders moved to accommodate passage in those areas: House Falls, Shenandoah Falls, and Seneca Falls. The remaining two sections of the canal, at Great Falls and Little Falls, both utilized stone and wooden lock systems to raise and lower boats for the drastic elevation changes of the Potomac Gorge. The canal at Great Falls, in particular, was the most robust of the company’s construction projects. Today you can find a National Civil Engineering Landmark plaque near Lock 1, commemorating the achievement of labor put forth to complete this endeavor.

The Canal Cut feature, Locks 2-5— where boats concluded their journey through this portion of canal and reentered the river—was constructed by blasting through 60 feet of solid rock to get to the river. This was the first time black powder was used for construction purposes. The Patowmack Canal was a budding nation’s first grand experiment using technology to harness nature in order to expand transportation, trade, and ultimately facilitate the economic growth of this new nation.


An entire town grew up around the construction site to serve as headquarters for the Patowmack Company and home for the workers. The town was named Matildaville by its founder, the Revolutionary War hero "Light Horse" Harry Lee. Harry Lee, the father of Robert E. Lee, named the town for his first wife, Matilda Lee.

Matildaville, at its height, boasted the company superintendent's house, a market, gristmill, sawmill, foundry, inn, ice house, workers' barracks, boarding houses, and a sprinkling of small homes. Boaters stopped here to wait their turn through the locks, to change cargo, or to enjoy an evening in town before continuing their journey.

Transportation on the River

Thousands of boats locked through at Great Falls, carrying flour, whiskey, tobacco, and iron downstream; carrying cloth, hardware, firearms, and other manufactured products upstream.

Vessels varied from crudely constructed rafts to the long narrow "sharper," a keelboat that could carry up to 20 tons of cargo. The trip took 3 to 5 days down to Georgetown and 10 to 12 days poling against the current back to Cumberland.

The Fate of the Canal and Matildaville

The greatest obstacle to the Patowmack project proved to be financial. High construction costs, particularly at the Great Falls section, and insufficient revenues bankrupted the company. Extremes of high and low water restricted use of the canal to only a month or two each year. The tolls collected could not even pay interest on the company debt.

The Patowmack Company succumbed in 1828, turning over its assets and liabilities to the newly formed Chesapeake and Ohio Canal Company. The new company abandoned the Patowmack Canal in 1830 for an even more ambitious undertaking: a man-made waterway stretching from Georgetown to Cumberland on the Maryland side of the river.

Built to support the canal industry, Matildaville's fate was tied to that of the Patowmack Company. Today, only a few fragile remains of Matildaville are visible.

Although the Patowmack Company was a financial failure, its builders pioneered lock engineering and stimulated a wave of canal construction important to the country's development.

George Washington did not live to see the completion of the navigation project that had been his obsession since youth. But he did take pride in visiting the canal during the construction to inspect its progress. He died in 1799, two years before the canal opened at Great Falls.

In the long run Washington's vision of a strong nation linked by trade came true. His frequent toast, "Success to the navigation of the Potomac!" became a footnote of American history.

A National Park

In 1930 Congress authorized this place of human history and natural beauty as a park. The National Park Service took on responsibility for its management in 1966.

Today Great Falls Park, a unit of the George Washington Memorial Parkway, protects and preserves the ruins of the Patowmack Canal and Matildaville.

The preservation of the Patowmack Canal is part of the Park Service's continuing efforts to protect and preserve special resources of the park.

The Patowmack Canal and Matildaville ruins are protected by the Archeological Resources Protection Act of 1979. This law prohibits excavation, removal, or displacement of archeological resources.

Last updated: September 1, 2019

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