Juvisy-sur-Orge (French pronunciation: [ʒyvizi syʁ ɔʁʒ] ⓘ, literally Juvisy on Orge) is a commune in the Essonne department in Île-de-France in northern France.
The site of the town has been occupied from ancient times; it is noted in Julius Caesar's book about the Gallic Wars.
The city is today known for Gare de Juvisy, the fourth largest and most-frequented railway station in the Grand Paris.
Regional Express Network) lines C and D. Starting from 1883, Juvisy-sur-Orge is the location of astronomer Camille Flammarion's observatory, which today belongs to the Société astronomique de France.
The town is also the site of the 1740 Pyramid erected to memorialize the work of Jean Picard and Nicolas Louis de Lacaille in measuring the Earth's circumference.