Wildlife conservation on private land is an important approach that is increasingly utilized to protect biodiversity and can help contribute to the 30 by 30 target of the Global Biodiversity Framework. In 2018, a Chilean non-profit conservation organization launched a land conservation programme aiming to build long-term partnerships with private landowners to protect critical habitat for threatened amphibians in Chilean Patagonia. Here we describe a new locality record of the micro-endemic, Endangered Barrio's frog Insuetophrynus acarpicus found at a site that joined the programme in 2020. Barrio's frog is ranked 11th in the list of Evolutionarily Distinct and Globally Endangered amphibians. Our systematic literature search showed that most aspects of the natural history and ecology of this species are unknown, limiting our ability to provide actionable science to inform its conservation. The newly described Barrio's frog population is the eighth known locality of this species and one of only three occurring within a protected area. Habitat quality assessments indicated optimal conditions for most of the measured habitat parameters in the high-gradient stream where the species occurs. This case study illustrates that long-term partnerships between private landowners and conservationists can be used as an effective tool to protect the habitat of highly threatened amphibians.