The Observatory is about 2 km east of Sidmouth and 0.5 km from the coast. It is on the north side of Salcombe Hill Road which runs between the town and Trow Farm, where it joins the east-west A3052.
At Sidford there is a junction with traffic lights where the north-south A375 crosses the east-west A3052. Travelling east from this junction, crossing the River Sid and starting to climb Trow Hill, one comes to Stevens Cross. Turn right here, going along Sid Road through Fortescue, and after 2km turn left up Salcombe Hill towards the Observatory.
The NLO can also be approached from the east by the unclassified road (narrow in places, signed 'Salcombe Regis 1') which leaves the A3052 at Trow Farm.