The Inner Sound is a strait separating the Inner Hebridean islands of Skye, Raasay and South Rona from the Applecross peninsula on the Scottish mainland.
The Inner Sound includes the deepest section of the UK's territorial waters, with a maximum depth of 1,062 feet. An area, over 1.5 miles (2.4 km) long and up to 0.25 miles (0.40 km) wide, exists below a depth of 960 feet (290 m), with a relatively flat bottom. There is another cleft 828 feet (252 m) deep, separated from the deeper bowl by an area of shallower water. A dive to examine the deeper trench found the bottom to be made up of bioturbated mud, with a steep slope towards the west of up to 60°.
Its Gaelic name, An Lighe Rathairseach, should not be confused with An Linne Rathairseach (the Sound of Raasay), its western neighbour. Together, they can be considered as southeastern arms of the Little Minch.
The Inner Sound is the location of BUTEC, a Royal Navy submarine sensor and emissions range.
Coordinates: 57°25′N 5°56′W / 57.417°N 5.933°W