Union Banks (Pagkakaisa Banks and Reefs) is a large drowned atoll in the center of Dangerous Ground in the Spratly Islands in South China Sea, west of the Philippine coast, containing islands and reefs whose ownership remains disputed and controversial. The closest atoll is Tizard Bank, due north of Union Banks. There are only two natural islands on the rim of the reef, Sin Cowe Island and Sin Cowe East Island.
The atoll is long from Johnson South Reef in the southwest to Whitson Reef in the northeast, and up to wide. Its total area measures . The central lagoon is up to deep.
Union Banks consists of the following islands and reefs, clockwise starting in the southwest corner:
Key: <span style="color: yellow;">yellow</span> = occupied by PRC; <span style="color: violet;">violet</span> = occupied by Vietnam
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