[7] On 15 September 1880, the town became the capital city of a special prison commune; the mayor was the Director of the Penitentiary Administration.

It is located on the Maroni River (in Dutch: Marowijne), opposite the town of Albina in Suriname which can be reached by ferry or pirogue.

[10] The places of birth of the 43,600 residents in the commune of Saint-Laurent-du-Maroni at the 2015 census were the following:[13] These were the countries of birth of the immigrants living in the commune of Saint-Laurent-du-Maroni at the 2009 census:[14] This river town has long been the headquarters of an important association for the protection of the environment: "Le pou d'agouti" (an environmental organisation named after an annoying local mite with an itchy bite[15] which strives for the protection of local and regional fauna and flora.

It is also the point of departure for several ecotourism circuits, most notably journeys upriver to explore the many creeks as well as the Amazonian rainforest; tourists can spend a night in the jungle in huts or tents.

A new port was recently built on the Maroni, but currently lacks proper wharf infrastructure and sufficient river depth.

On the road to Saint-Jean-du-Maroni (about 17 km (11 mi) south of St-Laurent, home of the former penal Camp de la Rélégation),[24] one can find many small shops owned by Saramakas selling the woodwork for which they are famous - especially chairs and tables.

[25] Two military units are stationed at St-Jean's Camp Némo: the Groupement du service militaire adapté (GSMA), which is part of the Ministry of Overseas France and is in charge of professional job reinsertion in the west of French Guiana; and the Maroni detachment of the 9th Marine Infantry Regiment whose job it is to patrol the river border and the jungles of the west of the département.In 2008, the two units has merged into the Regiment of the Adapted Military Service (RSMA).

[4] Bricks made from the local red clay were used by the convicts, who provided a free and never-ending workforce, to build a whole official and administrative district, starting with the main jailhouse itself, the Camp de la Transportation.

After the jailhouse was closed and the penal authority left in the early 1950s, these buildings suffered from lack of maintenance and interest, and were much damaged due to the harsh weather conditions in western French Guiana.

[28][29] Other notable sights from the penitentiary years include Saint-Jean-du-Maroni, formerly the Camp de la Relégation and today's main military HQ for western French Guiana.

Many of them nestle in little gardens, and in the gardens are palm trees and flame of the forest; cannas flaunt their bright colours and crotons their variety; the bougainvilleas, purple or red, riot profusely, and the elegant hibiscus offers its gorgeous flowers with a negligence that seems almost affected.

St Laurent de Maroni is the centre of the French penal settlement of Guiana, and a hundred yards from the quay at which you land is the great gateway of the prison camp.

These pretty little houses in their tropical gardens are the residence of the prison officials, and if the streets are neat and clean it is because there is no lack of convicts to keep them so.