Sanchong was called
Satengpo (), which literally means "The Third Plain" by the early settlers. The settlers from the modern-day
Xinzhuang area moved up north and named the plains they settle as "The First Plain" (頭前埔, located in modern-day Xinzhuang District), "The Second Plain" (二重埔, located in modern-day Sanchong) and The Third Plain. The district has been an important suburb of
Taipei. On 1 April 1962, Sanchong was upgraded from an
urban township to be a
county-administered city. On 25 December 2010 with the creation of
New Taipei City from former
Taipei County, Sanchong City was upgraded into a
district. ==Demography==