Bluemull Sound is the strait between Unst and Yell in Shetland's North Isles. A ferry service crosses it regularly. Cullivoe is on the Yell side, and the island of Linga lies in the strait.
The Sound was referred to as "Blumel sound" in early 1800 nautical references[1][2] It was later referred to as Bluemull Sound in 1865.[3] It is unclear why there is such a discrepancy in the name.