Trincomalee Harbour in the context of "Harbour"

A harbor (American English), or harbour (Commonwealth English; see spelling differences), is a sheltered body of water where ships, boats, and barges can be moored. The term harbor is often used interchangeably with port, which is a man-made facility built for loading and unloading vessels and dropping off and picking up passengers. Harbors usually include one or more ports. Alexandria Port in Egypt, meanwhile, is an example of a port with two harbors.

Harbors may be natural or artificial. An artificial harbor can have deliberately constructed breakwaters, sea walls, or jetties or they can be constructed by dredging, which requires maintenance by further periodic dredging. An example of an artificial harbor is Long Beach Harbor, California, United States, which was an array of salt marshes and tidal flats too shallow for modern merchant ships before it was first dredged in the early 20th century. In contrast, a natural harbor is surrounded on several sides by land. Examples of natural harbors include Sydney Harbour, New South Wales, Australia, Halifax Harbour in Halifax, Nova Scotia, Canada, and Trincomalee Harbour in Sri Lanka.

Cork Harbour (Irish: Cuan Chorcaí) is a natural harbour and river estuary at the mouth of the River Lee in County Cork, Ireland. It is one of several which lay claim to the title of "second largest natural harbour in the world by navigational area" (after Port Jackson, Sydney). Other contenders include Halifax Harbour in Canada, Trincomalee Harbour in Sri Lanka and Poole Harbour in England.

The harbour has been a working port and a strategic defensive hub for centuries, and it has been one of Ireland's major employment hubs since the early 1900s. Traditional heavy industries have waned since the late 20th century, with the likes of the closure of Irish Steel in Haulbowline and shipbuilding at Verolme. It still has strategic significance in energy generation, shipping, refining and pharmaceuticals development.