The Kui Ajiang (ชาวกวยอาเจียง) in Thailand are an Indigenous community living in the Northeast, along the border with Cambodia. Known as the ‘elephant people’, the Kui Ajiang are named for their history of catching wild elephants – a practice that came to an end sometime in the 1950s or 1960s. This talk takes the case study of the Kui people of Surin and their elephant heritage as a means of exploring issues of agency, authority, authenticity, and loss. This is done by looking at how different definitions of heritage (both natural and acultural) by the Thai state work exclude Indigenous Peoples from defining, managing, and protecting their heritage. The talk will begin with a wider-scale view of Thailand – the historical development of its heritage policies and approaches to culture and the environment and Indigenous rights from the colonial period up to the present, as well as a more in-depth view of Kui culture in Surin province. Over the course of fieldwork, I identified three Kui traditions that became ‘endangered’ following the end of elephant catching. In this talk, I will follow this endangerment, from why elephant catching ended to the community’s responses to this cultural threat.