The Governors of New York, New Jersey, Delaware, Maryland, and Virginia in 2009 signed the Mid-Atlantic Governors’ Agreement on Ocean Conservation. The Agreement established the Mid-Atlantic Regional Council on the Ocean (MARCO) as a partnership to address shared regional priorities and provide a collective voice. MARCO uses regional ocean planning as a means to advance priorities identified in the Governors’ Agreement. Ocean planning is a process to improve understanding of how ocean resources and places are being used, managed, and conserved, and to establish a common foundation that will guide actions to address the shared regional priorities. MARCO leverages existing state and federal resources, knowledge, and partnerships to build a stronger base of information and experience to make well-informed decisions in the best interest of the states and their constituents. Leading MARCO’s efforts is the MARCO Management Board, which comprises senior coastal managers and policy advisors from each of the five member states and is responsible for implementing MARCO’s regional priorities. By working together, while recognizing the partners’ varying respective interests and needs, MARCO provides the states with expanded capacity to address pressing management challenges to improve ocean health, achieve sustainable use of ocean spaces and resources, and grow the vital ocean-based economy.