This article describes a Mapmark standard setting procedure, developed under contract with the National Assessment Governing Board (NAGB). The procedure enhances the bookmark method with spatially representative item maps, holistic feedback, and an emphasis on independent judgment. A rationale for these enhancements, and the bookmark method, is presented, followed by a detailed description of the materials and procedures used in a meeting to set standards for the 2005 National Assessment of Educational Progress (NAEP) in Grade 12 mathematics. The use of difficulty-ordered content domains to provide holistic feedback is a particularly novel feature of the method. Process evaluation results comparing Mapmark to Anghoff-based methods previously used for NAEP standard setting are also presented.