Fort Spijkerboor was the most important fort in the northern front of the Stelling van Amsterdam. From here, the strategic dikes around the Beemster Ring Canal and the North Holland Canal were defended.
Fort Spijkerboor was also equipped with the heaviest artillery of all the forts in this section of the front. On the front end, even a rotating gun turret was fitted with two pieces of 10.5 mm calibre artillery with a range of no less than ten kilometres. This turret and guns are still present for viewing.
The two storey fort building was used as a prison on several occasions after World War I. The bars on the windows and the murals in the interior stem from those periods.