<P> Southern Vietnam includes the following subregions: </P> <Ul> <Li> South Central Coast (Nam Trung Bộ) </Li> <Li> Central Highlands (Tây Nguyên) </Li> <Li> Southeast (Đông Nam Bộ) </Li> <Li> Mekong River Delta (Đồng Bằng Sông Cửu Long) </Li> </Ul> <Li> South Central Coast (Nam Trung Bộ) </Li> <Li> Central Highlands (Tây Nguyên) </Li>

Why was vietnam divided into north and south