Mainland is usually the continental part of a region, as opposed to the islands nearby. Sometimes the residents are called "the Mainlanders". As a result of the usually larger area of mainland, there are significantly more mainlanders than islanders, and mainlander culture and politics sometimes threaten to dominate those of the islands.

Prominent Mainlands include:

• Mainland China, as opposed to the areas of Taiwan, Hong Kong and Macau (but including the island of Hainan)
• Mainland Canada, as opposed to Newfoundland
• Continental United States ("The Mainland"), as opposed to Hawaii and Alaska
• Mainland Japan and Honshu, as opposed to the rest of the Japanese islands.
• the Nova Scotian mainland, as opposed to Cape Breton Island
• Mainland Great Britain, as opposed to the Channel Islands, the Isle of Man or Northern Ireland

Occasionally two approximately equal sized islands may interchangely refer to each other as the Mainland, as in the North Island and South Island of New Zealand.

The term can also be used on multiple levels; for example to someone in Tasmania, continental Australia is the Mainland; but to residents of King Island, Flinders Island, and the other surrounding islands, Tasmania itself is the Mainland.