The Erie Canal is a canal that traverses east–west through upstate New York, eastern United States, as part of the cross-state route of the New York State Canal System (formerly known as the New York State Barge Canal). It was built to create a navigable water route from the Atlantic Ocean to the Great Lakes Basin, originally stretching for 584 kilometres (363 mi) from the Hudson River at Albany to Lake Erie in Buffalo. Completed in 1825, it was the second-longest canal in the world (after the Grand Canal in China) and greatly enhanced the development and economy of many major cities of New York, including New York City, Albany, Syracuse, Rochester and Buffalo, as well as the United States. This was in part due to the new ease of transporting salt and other necessity goods, and industries that developed around those.The canal was first proposed in the 1780s, then re-proposed in 1807, and survey was authorized, funded and executed in 1808. Its construction began in 1817 after proponents of the project gradually wore down its opponents; and it opened on October 26, 1825. The canal has 34 locks with an overall elevation difference of about 565 feet (172 m), starting upstream with Black Rock Lock and ending downstream with the Troy Federal Lock. Both locks are owned by the United States Federal Government.Prior to the opening of the canal, local transportation of bulk goods was limited to the use of pack animals who had a 250-pound (113 kg) maximum cargo capacity. In the absence of railways, water transport was the most cost-effective way to ship bulk goods.

Political opponents of the canal and of then-New York Governor DeWitt Clinton denigrated it as "Clinton's Folly" or "Clinton's Big Ditch". It was the first transportation system between the East Coast of the United States and the western interior that did not require portage. It was faster than carts pulled by draft animals and cut transport costs by about 95 percent. The canal gave New York City's port a strong advantage over all other U.S. port cities and ushered in the state's 19th century political and cultural ascendancy. The canal fostered a population surge in western New York and opened regions to settlement farther west. It was enlarged between 1834 and 1862. The canal's peak year was 1855, when 33,000 commercial shipments took place. In 1918, the western part of the canal was enlarged to become part of the New York State Barge Canal, which also extended to the Hudson River running parallel to the eastern half of the Erie Canal.

In 2000, Congress designated the Erie Canalway National Heritage Corridor to recognize the national significance of the canal system as the most successful and influential human-built waterway and one of the most important works of civil engineering and construction in North America. The canal has been mainly used by recreational watercraft since the retirement of the commercial ship Day Peckinpaugh in 1994, although the canal saw a recovery in commercial traffic in 2008.