
The Suez Canal is the most famous of them all. Opened in 1869, the canal connects the Red Sea to the Mediterranean Sea in Egypt. This allowed ships to not have to travel all the way around Africa to get to Europe from Asia.
The Panama Canal, opened in 1914, and connected the Atlantic and Pacific oceans through Panama. Once it was built, ships no longer had to travel all the way around South America to get from one coast of the U.S. to the other via oceans.
There are many inland canals that work in similar ways to allow ships easies passage throughout the United States. While they aren't as well-known as the Suez Canal or Panama Canal, they are just as important for shipping in the U.S.
The Intercoastal Waterway
Many of the main canals in the eastern part of the United States were built within what is known as the Intercoastal Waterway. It's a 3,000-mile inland waterway that stretches from Massachusetts to Florida, then over to Texas.
Some of this waterway is natural, while some was made possible through manmade canals. It was finished in 1949, and provides easy passage through the eastern to central part of the U.S. without having to expose ships to the hazards of the open sea.
Some of the major shipping canals in the U.S. that are found within the Intercoastal Waterway are listed below.
Cape Cod Canal in Massachusetts

The Cape Cod Canal located in Massachusetts connects Buzzards Bay to Cape Cod Bay. It's seven miles long and connects the part of land along Cape Cod to the mainland part of Massachusetts.
The canal first opened in 1914 on a partial basis, but was completed in full two years later by 1916. It was used prominently during World War II to protect shipping vessels from German U-boats who patrolled just offshore.
Point Pleasant Canal in New Jersey
Completed in 1925, the Point Pleasant Canal connects the Manasquan River and Manasquan Inlet with Bay Head Harbor, which is located along the northern end of New Jersey's Barnegat Bay.
The canal allows ships to travel up the river from the bay, and vice versa, serving many of the inland parts of the region. It served as a very important waterway to shippers in the region.
Cape May Canal in New Jersey

The Cape May Canal connects the Cape May Harbor at the southern tip of New Jersey to the Delaware Bay. It was completed during World War II, again as a way to stave off the threat of German U-boats.
The canal is only 2.9 nautical miles long, but is an essential route for ships to take up and down the eastern coast of the U.S., as well as up to the city of Philadelphia, Pennsylvania.
Chesapeake & Delaware Canal in Maryland and Delaware
The Chesapeake & Delaware Canal is 14 miles long. It's a deep ship canal that connects the Delaware River in the state of Delaware to the Chesapeake Bay in Maryland.
By constructing this canal, engineers were able to save shippers roughly 300 miles when they were traveling between Philadelphia or Wilmington, Delaware, down to Baltimore, Maryland.
Dismal Swamp Canal in Virginia and North Carolina

Originally opened back in 1805, the Dismal Swamp Canal is the oldest continually operating canal in the U.S. that was manmade. It was constructed because transportation was difficult between the sounds of North Carolina and the Tidewater regions in Virginia, where the sounds were entirely landlocked.
The canal was created to make transportation between these North Carolina regions and bigger markets at the time in Norfolk, Virginia, easier.
Even today, the canal is very important for commercial and recreational boating vehicles. The Atlantic Ocean off the coast of North Carolina can be very treacherous, so this canal provides safe shelter.
Other Shipping Canals Outside the Intercoastal Waterway
While the Intercoastal Waterway is home to some of the most important shipping canals on the eastern seaboard of the U.S., there are plenty of other important shipping canals in other parts of the country.
Some of those canals are listed below.

In 1856, construction on the Galveston and Brazos Canal was completed, paving the way for easier shipping along the Gulf Coast. The goal at the time was to connect some inland plantations that were operations to the shipping routes in the Gulf of Mexico.
When completed, the canal connected San Luis Bay with Oyster Creek. It eventually travels down to the East Union Bayou until it meets up with the Brazos River.
The Galveston and Brazos Canal also serves as a major way to ship goods along the Brazos to California.
The Great Lakes Waterway

One of the most important canals in the United States is actually a series of canals -- and it also runs through Canada. It's called the Great Lakes Waterway. This system combines manmade canals with natural channels to enable ships to travel through all of the Great Lakes in the northern United States and southern Canada.
All of the Great Lakes actually connected together as one big chain, but there are natural obstacles that stand in the way of ships traveling on them. This includes rapids in the St. Marys River as well as Niagara Falls.
The two major construction projects here were the Soo Locks, located between Lakes Superior and Huron, and the Welland Canal, located between Lakes Erie and Ontario.
Thanks to the Great Lakes Waterway, ships are able to all the way from the Atlantic Ocean to both Duluth, Minnesota on Lake Superior (2,340 miles) and to Chicago, Illinois on Lake Michigan (2,250 miles).
Combined with the Saint Lawrence Seaway, the Great Lakes Waterway represents perhaps the most important part that shipping canals in the United States play.