What Is Mainland UK? England, Wales, Scotland — Not Northern Ireland

Mainland UK (often **"Great Britain"** in geographic terms) refers to the **contiguous landmass** of the United Kingdom on the island of Great Britain, **excluding offshore islands** (Isle of Wight, Anglesey, Hebrides, Orkney, Shetland, etc.) and **Northern Ireland**.

Components

1. England — largest part. Borders: Wales (W), Scotland (N). Coasts: Celtic Sea, English Channel, North Sea, Strait of Dover.
2. Wales — west of England. Coasts: Irish Sea (N), Celtic Sea (S), Bristol Channel (SW).
3. Scotland — northern third of island. Border: England (S). Coasts: Atlantic (W/N), North Sea (E), North Channel (SW).

What's Excluded

• Northern Ireland — part of **UK** but on island of **Ireland** (not Great Britain).
• Offshore islands (Isle of Man, Channel Islands — Crown Dependencies, not UK).
• Overseas Territories (Gibraltar, Falklands, etc.).

Terminology precision:

• United Kingdom = England + Wales + Scotland + Northern Ireland.
• Great Britain = England + Wales + Scotland (the island).
• British Isles = Great Britain + Ireland + 6,000+ smaller islands (geographic, not political).