Montrouge is a commune in the southern suburbs of Paris, France. It is located 4.4 km. (2.7 miles) from the center of Paris. It is one of the most densely populated municipalities in Europe. After a long period of decline, the population has increased again in recent years.
Its name comes from the Latin words monte mount and rubeus red, meaning Red Mountain according to the reddish color of the ground. The name was mentioned in 1194.
In 1640, the plain of Montrouge became a reserve for royal huntings.
On January 1, 1860, the city of Paris was enlarged by annexing neighboring communes. On that occasion, the largest part of the commune of Montrouge was annexed to Paris, and forms now the neighborhood of Petit-Montrouge, in the 14th arrondissement of Paris. The remaining part of Montrouge was preserved as a rump independent commune.
In 1875, the commune gained a few thousand square metres from the neighboring communes of Châtillon and Bagneux (principally the quartier of Haut Mesnil).