Saisiyat community identify themselves as Saisiyat, and transliterated their name into Chinese as Sai Xia ethnic group.. According to the Saisiyat legend, the ancestors of all communities and ethnic groups come from the flesh, the bone, the stomach, and the intestines thrown in the sea of the child of a brother and a sister who survived the deluge. The Saisiyat people are distributed in northwestern Taiwan in two administrative regions: Hsinchu County and Miaoli County separated by Ergonji Mountain (Ngangihaw). The Saisiyat people in Hsinchu County settled in Da’ai Village (Sansama:an) and Huayuan Village (Mayhoman) on the Shangping River drainage basin in Wufeng Township. As they are surrounded by many Atayal communities, both ethnic groups influence each other culturally. The Saisiyat people in Miaoli County settled in Donghe and Nanhe drainage basin at the upstream of the Zhonggang River in Nanzhuang Township and the Shitan River drainage basin at the upstream of the Huolong River. Communities mainly settle in Donghe, Penglai, and Nanjinag villages in Nanzhuang Township and in Baisho Village in Shitan Township. Surrounded by Hakka Han communities, the Saisiyat people in Miaoli have been deeply influenced by local Hakka culture in daily life.
In the Qing dynasty, the Saisiyat expanded their territory to Sanwan and Toufen in Miaoli, bordering the Taokas (Taukat, plain indigenous people) in the West. The eastward movement of Hakka immigrants in Hsinchu and Miaoli after the mid-Qing dynasty disturbed the Saisiyat territory. As the global market of camphor expanded, armed cultivators began to invade Saisiyat territory, causing much nuisance to the Saisiyat. From then on, in addition to requesting rent from camphor developers, some Saisiyat people ran camphor businesses themselves. During Japanese colonization, the colonial government reckoned that the Saisiyat territory was the crown land. As this affected the camphor tax income and the ownership of the Saisiyat people, the expropriation resulted in a resistance called the Nanzhuang Incident in 1902. Later, the Saisiyat people in Hsinchu were recruited by the Hakka people in the armed resistance against the colonial government, resulting in the Beipu Incident of 1907. Due to the Hakka Han cultivation in the Qing dynasty and the camphor business competition of the colonial government during Japanese colonization, the Saisiyat began to decline, resulting in the ethnic relationships and cultural status today. In recent years, the Saisiyat people have settled in Taipei, Taoyuan, Hsinchu, and Miaoli.