Tongshan was originally knows as Pengcheng County, the latter merged into Xuzhou during the Yuan and the Ming dynasties, also in the early Qing dynasty. In 1733, as Xuzhou became a prefecture (
fu) from an independent department (
zhili zhou), its department proper was separated and renamed "Tongshan" (literally: copper-filled hill), which derives from an island in the
Weishan Lake. Tongshan was once the metropolitan county (
shou xian) of Xuzhou, thus it referred to the prefecture since 1912, until the Japanese Army captured the county and made Xuzhou City its urban area in 1939. The county was dissolved in 1952, but was restored in the next year. It became a district since 2010. ==Administrative divisions==