From Bergen op Zoom, the line consists successively of the fortresses Moermont (disappeared), Pinssen and De Roovere, the inundation plain Halsterens Laag, the fortress Steenbergen and finally fort Henricus.

By opening a sluice in the Steenbergse Vliet, seawater could flow from this last fort, causing the Halsters and Oudlands to flood low.

The line was extended south of Bergen op Zoom in the World War I to be able to repel a possible attack by England.

In 1809 an invasion of Zeeland by England was repulsed by French and Dutch troops of Napoleon.

On the other hand, in World War I, Germany could benefit from using the Antwerp harbour and the extra supply lines to Belgium.