Le terrain
The sector of the region of La Côte which is crossed by the fortified Line de la Promenthouse is composed of two different parts: the Jura incline in the upper part and the coastal plain of Lac Léman below. This zone has always been a passageway East to West between Geneva and Lausanne.
For an enemy approaching from the West, the situation of the fortified line chosen occupies the shortest distance between Jura and the Lac Léman. Furthermore, the terrain offers natural obstacles that, should be made use of. Such obstacles upon which the line was built are the rivers of the Combaz, La Serine and the Promenthouse.
Above, the rivers flow at the bottom of ravines with steep sides that cannot be accessed by the armoured tanks.
Further down, the artificial obstacles reinforce the natural obstacle of the river.
Our troops
The Frontier Battalion 218 Fusiliers was stationed in the sector Lac Léman to Begnins, with its command post in Gland. The Frontier Battalion 217 Fusiliers controlled the higher sector, from Bassins via Burtigny to St.Georges, with its command post in Bassins.
In 1939, each battalion was made up of military staff, a platoon armed with mortars, two platoons armed with infantry cannons, four companies of Fusiliers, a platoon armed with fusiliers and work garrisons in the bunkers.