Caithness was very important to the protection of the Scapa Flow anchorage and its naval facilities. It was so important that Caithness was closed off from the rest of Britain requiring a pass to enter and leave the county. The footprints of the many WW II airfields can still be seen as can the dummy airfield at Thrumster intended to draw bombing raids away from Wick. Many wartime buildings survive mainly re-used by local farmers.
Caithness also claims to be the location of the first German bomb to fall on the British Mainland. The bomb landed on moorland near Watten reputedly targeting a crofter who was heather burning.
The bomb crater still exists and a local crofter has a large fragment of the bomb casing.