Collins Reef
Collins Reef, also known as Johnson North Reef/Johnson Reef North; ; Roxas Reef ; Mandarin, is a Vietnamese occupied and controlled reef and the westernmost feature of Union Banks Atoll near the centre of Dangerous Ground in the Spratly Islands in the South China Sea. It is also claimed by China, Taiwan, and the Philippines.
Cô Lin Reef is located 8.1 nautical miles southwest of Sinh Tồn Island, approximately 3.9 nautical miles northwest of Gạc Ma Reef, and 7 nautical miles west of Len Đao Reef. It is essentially a triangular coral reef with slightly curved sides, each side measuring approximately 1 nautical mile in length. This reef is submerged underwater during high tide and only a few rocks emerge during low tide. The area of the Cô Lin Reef coral reef is approximately 2.05 km2.
Administrative maps all use the proper noun “Cô Lin” while the common noun used to describe the entity is “reef.” Geographically, Cô Lin Reef is not an island but a coral reef.
The area features the Cô Lin Island architectural complex, comprising a military outpost connected by a bridge to a multi-purpose cultural center located 65 meters away. The geographical coordinates inscribed on the sovereignty marker of Cô Lin Island are 9°46′25″N 114°15′19″E.
In June 2025, Vietnam began land reclamation and expansion activities at Cô Lin Island. By 2025, the approximate area of the island will be 5 hectares.