This resource is part of a series of comprehensive guides on some of the most challenging components of ILF program implementation identified through extensive research and interviews with operating ILF programs and other mitigation stakeholders. These guides help address perennial problems for ILF programs by identifying specific challenges, providing detailed recommendations on ways to meet these challenges, and including examples or case studies of programs to illustrate effective approaches to implementation. This guide provides an overview of regulatory requirements and common challenges associated with compensatory mitigation project review and approval for ILF programs. It then describes actions to consider for ILF programs to address these challenges, both internally and in working with the Interagency Review Team.