Dolmen de la Fontaine au Son, Neolithic dolmen in Saint-Léger-de-Montbrillais, France.

The Dolmen de la Fontaine au Son is a Neolithic tomb built from sandstone slabs in the Vienne department of western France. This site actually contains two separate structures: one retains its original form while the other shows signs of deterioration with scattered blocks.

These tombs were built around 5000 years ago during the Neolithic period, when people in this region constructed shared burial sites from local stone. The structures received official recognition as historical monuments in 1955, ensuring their protection.

The two monuments stand about 30 metres apart on either side of the Impasse de Rabaté, beside the Fontaines de Son water treatment plant, which keeps the name alive. The western Dolmen 1 is the larger and better preserved; the eastern Dolmen 2 is fenced off, partly for the plant and partly because of its risky condition. Both were classed as monuments historiques on 26 October 1955.

The site is open and accessible at any time without fees, located in a rural setting. Wear sturdy shoes since the ground can be uneven and vegetation may partially cover some areas of the stones.

Dolmen 1's covering table is now broken into two parts; it rests on three long upright stones, with a fourth overturned and a fifth visible beneath the table possibly serving as the head slab. Old plans and sketches show the monument has changed little since the 19th century.