China’s coastline covers approximately 14,500 km (around 9,010 mi) from the Bohai gulf in the north to the Gulf of Tonkin in the south. Most of the northern half is low lying, although some of the mountains and hills of Northeast China and the Shandong Peninsula extend to the coast. The southern half is more irregular. In Zhejiang and Fujian provinces, for example, much of the coast is rocky and steep. South of this area the coast becomes less rugged: Low mountains and hills extend more gradually to the coast, and small river deltas are common.