The United States has substantive interests within the boundaries of Planning Domain 1, and, in March 2015, scientists from the U.S. Antarctic Marine Living Resources Program hosted a domestic workshop to develop background information relevant to the establishment of one or more marine protected areas (MPAs) therein. Key products from the workshop include a list of the types of specific objectives that U.S. stakeholders have for MPAs in Domain 1, a map of the areas that U.S. stakeholders consider to be priorities for spatial protection, and estimates of “conservation targets” that can be inferred from these priorities. The list of specific objectives included “protect krill spawning and larval development,” “study climate impacts separate from fishing,” “preserve the integrity of existing studies,” and ten other candidates. Participants at the workshop prioritized protection of the continental shelf and inshore waters along the western coast of the Antarctic Peninsula, from around Alexander Island and the Marguerite Bay northeast to the tip of the peninsula and Joinville Island and including various islands and archipelagos such as the South Shetland Islands. Consistent with these protection priorities, conservation targets were generally highest for objects that occur inshore or over the continental shelf (e.g., the summer foraging habitats of Pygoscelid penguins) and lowest for objects that occur farther offshore (e.g., the marginal ice zone during winter, the winter foraging habitats of chinstrap penguins, and many seamounts).