Montenay is a commune of 1 399 people (1999). It is found in the region Pays de la Loire in the Mayenne department in the northwest of France. The name of the place occurred as Montaniaco in the ninth century, and as Monteneio en 1225. It probably comes from the Latin Montanus. The area was probably settled in Neolithic times (5000-3000 BC). There is a dolmen and a groove nearby. The groove is called St. Guillaume's stone, and is located about 3km from the village.