The place now called Sandimen carries a Paiwan name that ethnic Chinese settlers translated into Hokkien using characters chosen for their sound rather than their meaning — a practice called homophonic translation that was common when languages met without a shared script. Under Japanese colonial rule the area had a different administrative designation, grouped together with the territories of modern-day Majia Township and Wutai Township under the governance of Takao Prefecture. After Taiwan's handover from Japan to the Republic of China in 1945, the area became Sandimeng Township, then was renamed again in 1947 to Sandi Township. Through all these official changes, the Taiwanese pronunciation — Soaⁿ-tē-mn̂g — persisted in everyday use among local residents. In August 1992, the township settled on its current name: Sandimen. The history of the name is itself a miniature history of how southern Taiwan's mountain communities navigated successive waves of outside administration, each of which arrived with its own naming conventions and bureaucratic frameworks.

Sandimen's population is primarily Paiwan, with a significant Rukai minority — and both communities maintain cultural traditions that are actively practiced rather than merely preserved. The Paiwan are known across Taiwan for their artistic richness: intricate beadwork using glass beads of specific colors and patterns, woodcarving with motifs that carry genealogical and ceremonial meaning, and a social system organized around noble and commoner distinctions expressed partly through the right to use certain designs and objects. Rukai culture shares some aesthetic overlaps with Paiwan but has its own distinct traditions, including the lily flower as a mark of purity for women and hunting achievement for men. Both peoples traditionally built in slate — flat stones quarried from mountain outcrops, stacked to create homes whose thick walls regulate temperature in ways that suit the subtropical mountain climate. In Sandimen's villages, slate-stone architecture is not merely historical: it is a built expression of identity and belonging.

The township covers 196.4 square kilometers — a substantial area of mountain terrain for a population of roughly 7,700 people. The ten administrative villages are distributed across that terrain: Anpo, Dalai, Dashe, Dewen, Jingshan, Jingye, Koushe, Mani, Saijia, and Sande. The low population density reflects the mountain character of much of the township, where forested ridges and river valleys separate communities that were once even more physically distinct from one another before road construction linked them more directly. During the Japanese colonial era, Sandimen was administered together with Majia and Wutai as part of a mountain district governance structure that grouped indigenous communities across a broad arc of the northern Pingtung mountains. After 1950, when Pingtung County was formally established, Sandimen became one of its mountain indigenous townships — a designation that carries specific legal and administrative meaning under the Republic of China's framework for indigenous governance.

Among Sandimen's notable landmarks is the Guchuan Bridge, which serves as one of the gateways to the mountain country beyond the township. The bridge marks a transition point from the plains-edge landscape of the lower township to the deeper mountain terrain that connects Sandimen to the Maolin National Scenic Area — a scenic designation that formally encompasses parts of Sandimen Township along with Maolin and Liouguei Districts in Kaohsiung. The Maolin area's purple crow butterfly wintering grounds, the hot springs of Liouguei, and the cultural landscapes of the Rukai and Paiwan communities are all accessible through this mountain corridor. Sandimen functions in this geography as both a gateway and a destination in its own right — a community with its own character, not merely a transition point on the way to scenery further up the mountain.

Sandimen has its own township government, its own administrative identity, and — in the names, languages, and practices of the Paiwan and Rukai communities who live here — its own voice. The official renaming history, from Paiwan original to Hokkien transliteration to Japanese designation to various Republic of China versions, reflects the layers of authority that have moved through this area across a century and a half. But the people who have lived through all those name changes are still here. The Paiwan pronunciation that persisted in everyday use even when the official name was something else tells its own story: languages and cultures do not simply accept the administrative labels placed upon them. In Sandimen, the past and present coexist in the language spoken at home, the designs carved into wood and beaded into jewelry, and the ceremonies that mark the seasons of life in a mountain community that has endured.