Montagne d'Argent, Mountain in northeastern French Guiana

This summit rises 132 meters above sea level and overlooks the Oyapock River estuary near Pointe Béhague. The site covers roughly 7 square kilometers and is now protected by the Conservatoire du littoral.

A Jesuit establishment came first; in 1854 one of French Guiana's earliest penal colonies opened on the site. Living conditions were so harsh that the authorities closed it in 1861, then reopened it from 1891 to 1898 before selling the land to a Chinese owner. The Kabyle outlaw Ahmed ou Essaid Abdoun, arrested in 1884, was among the prisoners who escaped from here.

Rock carvings found here show that indigenous peoples lived in this area long before European arrival. These ancient marks remain visible today and tell the story of the earliest inhabitants of this coastal region.

The site lies on the Oyapock estuary near Pointe Béhague, in the commune of Ouanary, and is protected by the Conservatoire du littoral since 1998. There is no marked trail or visitor facility; the ruins stand in abandoned forest reached by boat, so arrange transport and a local guide beforehand. Wear boots and long sleeves, as the ground is uneven and overgrown.

The hill's name comes from the bois canon trees that covered it when explorers first saw it; their leaves have a silvery sheen. The 132-metre summit is also where 22 petroglyphs were found, the reason the Conservatoire du littoral took the site under protection in 1998.