Marine protected areas (MPAs) are generally defined as areas reserved by law or other effective means to protect part or all of the enclosed environment. This report identifies a number of issues related to establishing MPAs in the United States. It begins by defining the concept and administrative actions taken to provide spatial protection in marine areas. It then considers some of the key issues and potential benefits and costs of designating additional MPAs. It concludes by considering potential areas of congressional interest for the 111th Congress. Existing federal laws related to the use of MPAs are summarized in the Appendix.