The Cromarty Firth (ˈkrɒmərti; Caolas Chrombaidh ˈkʰɯːlˠ̪əs̪ ˈxɾɔumbaj; literally "kyles [straits] of Cromarty") is an arm of the Moray Firth in Scotland.
The entrance to the Cromarty Firth is guarded by two precipitous headlands; the one on the north high and the one on the south high — called "The Sutors" from a fancied resemblance to a couple of shoemakers (in Scots, souters) bent over their lasts. From the Sutors the Firth extends inland in a westerly and then south-westerly direction for a distance of . Excepting between Nigg Bay and Cromarty Bay where it is about wide, and Alness Bay where it is wide, it has an average width of . The southern shore of the Firth is formed by a peninsula known as the Black Isle. Good views of the Cromarty Firth are to be had from the Sutors or Cnoc Fyrish.
At its head the Firth receives its principal river, the River Conon, other rivers include the Allt Graad, Peffery, Sgitheach, Averon and Balnagown. The Dingwall