| Marchais | |
| Commune Status: | Commune |
| Arrondissement: | Laon |
| Canton: | Villeneuve-sur-Aisne |
| Insee: | 02457 |
| Postal Code: | 02350 |
| Demonym: | Marchaisiens |
| Mayor: | Christophe Hanon[1] |
| Term: | 2020 - 2026 |
| Intercommunality: | Champagne Picarde |
| Coordinates: | 49.5844°N 3.8175°W |
| Elevation M: | 80 |
| Elevation Min M: | 70 |
| Elevation Max M: | 110 |
| Area Km2: | 15.3 |
Marchais (in French pronounced as /maʁʃɛ/) is a commune in the Aisne department in Hauts-de-France in northern France. It takes its name from the Latin 'mercasius' or marshland.
The 16th century Chateau de Marchais is a private residence of the Princes of Monaco, since being acquired in 1854 by Charles III.[2] It was built in the 16th century by Nicolas de Longueval, Comte de Bossut.[3] [4] He was accused of treason, though, and to save his life, he surrendered his castle and lands to Charles, Cardindal of Lorraine.[3]
In 1906, Maurice Léger made a prototype helicopter flight at Marchais.