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 . 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 mountain.