Calbha Mòr lies north of the Kylesku Bridge and west of the Duartmore forest in a location that is relatively inaccessible from the A894 road. It is 70 hectares (170 acres)[2] in area and comprises two rounded hills, the higher of which reaches 67 metres (220 ft).[2]
It is separated from its smaller neighbour, Calbha Beag, by a channel 11 metres (36 ft) deep.[4] Calbha Beag is 45 hectares (110 acres) in area.[2]
The sheltered Bàgh Chalbha lies to the east[5] and a large escape of fish from a fish farm here took place in 2003.[6]