Many land managers in the US West increasingly are trying to expand the pace and scale of wildfire risk reduction by working across larger landscapes and ownership boundaries. What does it take to truly coordinate this work at scale among organizations with different missions and mandates? From an applied social science perspective, we will use case studies of both forests and rangelands in Colorado, Utah, New Mexico, Oregon, and Idaho to explore this question, providing several actionable examples of how boundaries may be spanned for more collective action.