The study identifies 16,825 unprotected terrestrial sites, spanning ~164 Mha, that harbor rare and threatened species, termed "Conservation Imperatives." These sites are critical for preventing imminent extinctions and should be prioritized for conservation action over the next 5 years as part of a broader strategy to expand the global protected area network. Protecting these sites would cost approximately US$169 billion (90% probability: US$146–US$228 billion), with the tropical subset costing about US$34 billion (90% probability: US$29.2–US$45.6 billion) per year over 5 years. Globally, 38% of these sites are adjacent to or within 2.5 km of existing protected areas, potentially reducing land acquisition and management costs. The study highlights the urgent need to prioritize the conservation of habitats of rare and threatened species as part of a larger global biodiversity strategy. Conservation Imperatives represent the most biologically important and threatened places to protect, acting as "anchor points" for regional-scale conservation planning under the 30×30 goal. The study also emphasizes the importance of multiple approaches to meet long-term protection goals, including providing rights and titles to Indigenous Peoples and Local Communities (IPLCs), government designation of new protected areas, and land purchase or long-term leasing of privately held lands. The results show that the current expansion of global protected areas has only incorporated 7% of sites harboring range-limited and threatened species, highlighting the need for renewed urgency to conserve these habitats. The study concludes that Conservation Imperatives can contribute to a science-based priority-setting strategy for expanding the global protected area network to at least 30% by 2030, in line with ambitious targets outlined in the Kunming-Montreal Global Biodiversity Framework.The study identifies 16,825 unprotected terrestrial sites, spanning ~164 Mha, that harbor rare and threatened species, termed "Conservation Imperatives." These sites are critical for preventing imminent extinctions and should be prioritized for conservation action over the next 5 years as part of a broader strategy to expand the global protected area network. Protecting these sites would cost approximately US$169 billion (90% probability: US$146–US$228 billion), with the tropical subset costing about US$34 billion (90% probability: US$29.2–US$45.6 billion) per year over 5 years. Globally, 38% of these sites are adjacent to or within 2.5 km of existing protected areas, potentially reducing land acquisition and management costs. The study highlights the urgent need to prioritize the conservation of habitats of rare and threatened species as part of a larger global biodiversity strategy. Conservation Imperatives represent the most biologically important and threatened places to protect, acting as "anchor points" for regional-scale conservation planning under the 30×30 goal. The study also emphasizes the importance of multiple approaches to meet long-term protection goals, including providing rights and titles to Indigenous Peoples and Local Communities (IPLCs), government designation of new protected areas, and land purchase or long-term leasing of privately held lands. The results show that the current expansion of global protected areas has only incorporated 7% of sites harboring range-limited and threatened species, highlighting the need for renewed urgency to conserve these habitats. The study concludes that Conservation Imperatives can contribute to a science-based priority-setting strategy for expanding the global protected area network to at least 30% by 2030, in line with ambitious targets outlined in the Kunming-Montreal Global Biodiversity Framework.