The designations are outlined in the Cultural Heritage Preservation Act [zh], and monuments are preserved by the Bureau of Cultural Heritage, a subdivision of the Executive Yuan.
According to the Cultural Heritage Preservation Act, Chapter 1, Section 3, historic sites are defined as "architectural works and its ancillary facilities built for the needs of human life, which are of outstanding universal value from the point of view of history, art or science.
Subsequent revisions to the act redefined the levels into the designations used today.
As of March 16, 2020, there are 967 historic sites protected under the Cultural Heritage Preservation Act, with 107 designated as national monuments.
Notably, there are no national monuments in eastern Taiwan, though Batongguan Trail does cross into Hualien County.