Sanchong is bounded to the north and northwest by Luzhou, Wugu, the west by Xinzhuang, and is separated from Taipei City by the Tamsui River.

Sanchong was called Satengpo (Chinese: 三重埔; Pe̍h-ōe-jī: Saⁿ-têng-po͘ / Sam-tiông-po͘),[3] which literally means "The Third Plain" by the early settlers.

On 1 April 1962, Sanchong was upgraded from an urban township to be a county-administered city.

The Taoyuan Airport MRT also stops at Sanchong station.

It is also connected to Xinzhuang, Luzhou, Wugu, and Banqiao District.