From 2008–2013, the David and Lucile Packard Foundation carried out a time-limited, six-year strategy to study, understand, protect, and restore biologically important and iconic regions of western North America. Through the Western Conservation Subprogram, the Foundation invested more than $122 million to advance land conservation, public policy, and conservation funding measures in California, the Colorado Plateau, and northwestern Mexico. The Foundation also invested in strategic opportunities that benefited the western region as a whole, including opportunities to conserve private land, strengthen land trusts, and advocate for federal conservation funding and tax policy. To assess the impact of our Western Conservation Subprogram’s approach and investments, the Foundation commissioned California Environmental Associates (CEA) to conduct a third-party evaluation. The Western Conservation Evaluation summary details the successes, challenges, and lessons learned throughout the subprogram’s history.