Cromarty Firth

Inlet in Highland unitary authority, Scotland, north of the Moray Firth, extending for 29 km/18 mi, with a width of up to 8 km/5 mi, and depth of 9–60 m/20–196 ft. Almost landlocked, it is entered by a narrow strait between two promontories, the North and South Sutors. During World War II, it was used as a safe harbour by the British navy. It has since been used as a servicing area for oil rigs.

In the 19th century, the Scottish writer and geologist Hugh Miller discovered fossilized fish in the local red sandstone, including Pterichthys and Osteolepis.