Ouvrage Saint-Roch is a work (gros ouvrage) of the Maginot Line's Alpine extension, the Alpine Line, also known as the Little Maginot Line. Small for a gros ouvrages, the ouvrage consists of one entry block, one artillery block and two observation blocks overlooking Sospel at an altitude of 426 metres (1,398 ft). The position is located just to the southwest of Sospel, its entrance block in a narrow valley and the artillery block on the other side of the ridge overlooking Sospel. The ouvrage is laid out along a single line, with the entry block to the rear, immediately followed by the usine, with barracks farther along and Blocks 2 and 3 at intervals. The position's main armament is concentrated in Block 4, a massive blockhouse designed to protect against rockfalls from higher up the mount