Thurso is the northernmost town on the British mainland, situated at the northern extreme of the A9 road, the main road linking Caithness with the south of the country, and is 20 miles (32 km) west of John O' Groats and 21 miles (34 km) northwest of Wick, the closest town.
Thurso lies as far north (59 degrees of latitude) as the Alaskan state capital of Juneau.
The town is within the Parish of Thurso, which has the parishes of Olrig and Bower to the east, Halkirk to the south, and Reay to the west.