Montlhéry is a commune in the Essonne department in Île-de-France in northern France. It is located 26 km from Paris. Montlhéry lay on the strategically important road from Paris to Orléans. Under the Merovingians, it was owned by the church in Reims and in 768 it was given to the abbey of St. Denis in Paris. It was the site of a number of battles between the lords of Montlhéry and the early Capetian monarchy.