The following is a list of Sites of Special Scientific Interest in the Caithness Area of Search. For other areas, see List of SSSIs by Area of Search.
- Achanarras Quarry
- Banniskirk Quarry
- Beinn Freiceadain and Ben Dorrery
- Berriedale Cliffs
- Berriedale Water
- Blar Nam Faoileag
- Broubster Leans
- Burn of Latheronwheel De-notified (confirmed) on 3 February 2012
- Castle of Old Wick to Craig Hammel
- Coire na Beinne Mires
- Craig Hammel to Sgaps Geo
- Dirlot Gorge
- Dunbeath Peatlands
- Dunbeath to Sgaps Geo
- Dunbeath Water
- Duncansby Head
- Dunnet Head
- Dunnet Links
- East Halladale
- Hill of Leodebest De-notified (confirmed) on 3 February 2012
- Hill of Warehouse
- Holborn Head
- John o' Groats
- Knockfin Heights
- Knockinnon Heath
- Lambsdale Leans
- Langwell Water
- Leavad
- Loch Calder
- Loch Caluim Flows
- Loch Heilen
- Loch Lieurary
- Loch of Durran
- Loch of Mey
- Loch of Wester
- Loch of Winless
- Loch Scarmclate
- Loch Watten
- Long Berry Coast
- Lower Wick River
- Morven and Scaraben
- Moss of Killimster
- Newlands of Geise Mire
- Oliclett
- Ousdale Burn
- Pennylands
- Pentland Firth Islands
- Phillips Mains Mire
- Red Point Coast
- Reisgill Burn
- River Thurso
- Rumsdale Peatlands
- Sandside Bay
- Shielton Peatlands
- Sletill Peatlands
- Spittal Quarry
- Strathmore Peatlands
- Stroma
- Stroupster Peatlands
- Thrumster Mill Loch
- Ushat Head
- Westerdale Quarry
- Westfield Bridge
- Weydale Quarry
- Wick River Marshes