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.