San Andrés Archipelago
The San Andrés Archipelago is situated in the southwestern regions of the Caribbean Sea, located off the Nicaraguan and Honduran coasts of eastern Central America and to the southwest of Jamaica. The archipelago consists of the two main islands of San Andrés and Providencia (Old Providence), plus several atoll-like reefs and submerged reef-topped carbonate platforms. In total, the land area of the group amounts to 52.5 km² spread throughout an area of around 350,000 km². They are a possession of Colombia, forming the Departamento de San Andrés y Providencia.
The major landmasses are located in the south: Isla de San Andrés (26 km²) and Isla de Providencia (17 km²), both of which are inhabited. The smaller island of Santa Catalina (2 km²) — which lies within the same barrier reef system that also encloses Providencia — is the only other inhabited member of the archipelago. Several cays and islets are located within the lagoons or upon the reefs that surround the main islands.
To the southeast of San Andrés lie the small reefs that contain the Cayos del Este Sudeste and the Cayos de Albuquerque — all other members of the group are located to the north, northwest and west of the Isla de Providencia. These include the Roncador Bank, the large Serrana and Quita Sueño banks, Serranilla Bank, Bajo Nuevo and the completely submerged Alice Shoal. These rees and banks also contain numerous small sand cays, many of which are vegetated. Also within the region, but not part of the archipelago, are other carbonate platform bank formations such as Rosalind Bank and Thunder Knoll.
Since November 2000 the archipelago and its waters have been under some degree of protection as the Seaflower Biosphere Reserve — part of UESCO's Man and the Biosphere programme — which aims to "reconcile the conservation of biodiversity in terrestrial and coastal ecosystems with its sustainable use". The Seaflower Reserve was set up to balance tourism and population growth with the coral reef, mangrove, and dry tropical forest environments that are currently under threat.