Ershui encompasses 29.44 square kilometres (11.37 sq mi) and a population of 14,080, including 7,421 males and 6,659 females as of March 2023.

The first inhabitants first came from Fujian, mainland China to Lukang, Changhua County, and then to the foothills of the Bagua mountain range.

Finally, the construction of a pineapple canning plant in 1932 began an economic boom for Nisui, making it the most prosperous town in the Choshui River region at the time.

[4] The township comprises 17 villages: Changhe, Dayuan, Ershui, Fuxing, Gehe, Gexing, Guanghua, Guozun, Huimin, Shangli, Shenghua, Shiwu, Wenhua, Wuba, Xiuren, Yuanquan and Yumin.

However, the local rock macaque preservation society has urged people not to feed them, since it reduces their ability to forage on their own, and overpopulation can also cause starvation.