Quélern is a hamlet in Roscanvel, in the department of Finistère (Brittany), in western France.
The Quélern lines defended the entrance to the goulet de Brest against capture from behind the defences of the Roscanvel peninsula.
They are 1.22 km long and form the only surviving non-urban line of fortifications in France.
[1] The lines still serve a strong geostrategic function and the area is still military land with no public access.
[1] From 1852 to 1854, a fort known as the réduit de Quélern was built to plans by Vauban, with modifications.