Côte d'Émeraude

{{Infobox former country

| native_name            = Colonie Royale de Côte d'Émeraude
| conventional_long_name = Royal colony of Côte d'Émeraude
| common_name            = Côte d'Émeraude
| image_flag             = Côte d'Émeraude.png
| image_coat             = França Equinocial.svg
| capital                = Saint-Louis
| common_languages       = Lysian, indigenous languages
| religion               = Tacolism, indigenous religions
| demonym                = Lysian
| government_type        = Colonial entity
| leader1                = Jean de Léry
| leader2                = [[Charles de la Roncière]
| year_leader1           = 1633-1659
| year_leader2           = 1659-1689
| legislature            = Superior Concil
| event_start            = Foundation from Lysia
| date_start             = 18 March
| year_start             = 1633
| event_end              = Emerald War
| date_end               = 15 January
| year_end               = 1689
| today                  = Pecario
| currency               = Lysian Franc

}}

Côte d'Émeraude was the contemporary name given to the Lysian colony in the 17th century in Mesothalassa. It was established on the western coast of Mesothalassa, and was mostly inhabited by Lysian settlers. The colony was renowned for its rich natural resources, including its emerald mines. Over time, Côte d'Émeraude prospered, attracting the interest of several regional powers. However, tensions were frequent with his neighbor the Kingdom of Pecario.

In 1687, the Emerald War broke out between the colony and Pecario, resulting in the conquest of the colony by Pecario in 1688. The war ended in 1689 with the signing of the Treaty of Saint-Louis, which marked the submission of Côte d'Émeraude to Pecario, and the incorporation of the colony into the kingdom of Pecario.

Despite its disappearance as a distinct political entity, Côte d'Émeraude left a lasting legacy in the region, particularly in its cultural traditions and architectural heritage.