The name Cat Ba is derived from a legend that back in the day of wartime, woman in the region took the responsibility of the rear for man to fight in the front. The name Cat Ba is originally Cac Ba which means Women. An adjacent island is named Cat Ong (Cac Ong – Men.)
Lan Ha Bay is located in in the north of Ha Long Bay and Northwest of Cat Ba Island. It spans an area of 70 km2, contains 400 small islands in various shapes and sizes. Unlike Ha Long Bay, almost every island in Lan Ha Bay is covered by lush green foliage.