They are a significant group, since Yell and Unst are the second and third largest islands in the archipelago, and also the third and fourth most populous (Whalsay, which is not in the group, is the second most populous). Combined, their total land area is far larger than the rest of the Shetland Islands (excluding Mainland) combined.
The group also contains the most northerly land of the United Kingdom and Shetland at Out Stack near Muckle Flugga, and its most northerly settlement Skaw on Unst. These also happen to be the most northerly British territorial claims currently in existence, since Canadian independence. In similar fashion, Britain's most northerly maritime claims are also based on these islands, having great effect on its fishing and oil industries.
Travellers do not encounter any further land masses between Out Stack and the North Pole if heading directly north.
Other British records include -
- Most northerly castle Muness Castle
- Most northerly post office - formerly Haroldswick now Baltasound
- Most northerly lighthouse - Muckle Flugga
- Most northerly road
- Most northerly brewery - Valhalla Brewery
- Most northerly coastline - Hermanness
- Most northerly church - Haroldswick Methodist Church 
- Most northerly ferry route - Gutcher (Yell) to Belmont (Unst)
- Most northerly "wood" - near Baltasound
The regular ferries are the most northerly scheduled routes in the British Isles (excluding those going to the Faroes and Iceland). They operate between Yell and Unst, Yell and Fetlar and Yell and Mainland.