Caofeidian District (simplified Chinese: 曹妃甸区; traditional Chinese: 曹妃甸區; pinyin: Cáofēidiān Qū), formerly Tanghai County (唐海县; 唐海縣; Tánghǎi Xiàn), is a district of Tangshan, Hebei, People's Republic of China, along the coast of the Bohai Sea. As of 2003, it had a population of 140,000 residing in an area of 725 km2 (280 sq mi). The district's administration is highly unusual in that apart from its seat, (唐海镇) and two other towns (滨海镇) and (柳赞镇) the rest of its administrative units are informal, mostly being farms.