This small strongpoint stands at the western edge of the entrance to the port of Dunkirk.
To the east is the mole and beach where Allied forces evacuated Dunkirk in 1940. Of course, this site wasn't built until later and it features two remaining casemates, both of which can be visited via a long drive along the protective berm which banks the Canal de Bourbourg. A bridge which linked the site to the east mole area is now closed to the public, hence the long drive from the west to this site.
The R630 casemate is a heavy duty machine gun emplacement and would have featured a 4.7cm Skoda gun while the L409 was built for a 3.7cm anti-aircraft gun.