The invasion of Cayenne in early 1809 was a significant military engagement during the Napoleonic Wars, orchestrated by a coalition of British, Portuguese, and colonial Brazilian forces. The strategic importance of Cayenne, located on the northeastern coast of South America, was central to this operation, as it served as a French possession that could threaten British trade routes and maritime interests in the Atlantic. With the rise of Napoleon Bonaparte's influence, Britain sought to undermine French control in various territories, leading to alliances with other colonial powers in the region.

On January 6, 1809, the allied forces landed near Cayenne, facing a relatively small French garrison. The military campaign was characterized by the use of naval support, which was crucial in securing landing zones and logistical supplies. As the coalition forces advanced, they encountered resistance from French troops, but the morale and numbers of the invading army played a critical role in the success of the operation. Local populations were also significant players in this conflict, as many sought to resist French rule and expressed willingness to collaborate with the invading forces.

The occupation of Cayenne marked a pivotal point in the regional dynamics of South America during this era. The successful invasion not only disrupted French operations in the area but also demonstrated the effectiveness of combined military strategies among colonial forces. This collaboration paved the way for future military alliances and engagements against French and Spanish presences in South America throughout the Napoleonic Wars.