Expanding learning time has become a leading strategy for closing the achievement and opportunity gaps that plague high-poverty schools in particular. With more time, educators are able to deepen the curriculum, embed enrichment classes and activities, and engage in frequent opportunities for teacher collaboration and professional development. Despite the accelerating momentum to expand learning time, little is known about the universe of expanded-time (ET) schools across the country. This remains largely a decentralized movement, with entrepreneurial endeavors that break from the conventional school calendar still the predominant mode for becoming an ET school. In an effort to better define and identify the diverse and growing cohort of ET schools, the National Center on Time & Learning (NCTL), an organization dedicated to re-designing and expanding school time to improve opportunities and outcomes for all students, has developed a database to collect and present the latest information. Documenting the 1,002 schools in the NCTL Database as of January 2012, "Mapping the Field" provides analysis of meaningful trends and key characteristics in this exciting educational arena. Like NCTL's first expanded-time schools report, which was released in late 2009, the data explored in these pages represent a snapshot of an ever-changing and burgeoning field. Indeed, as the data make clear, that field is dynamic, like the database itself, with new ET schools being identified and added on an on-going basis. By capturing, analyzing, and presenting the relevant school-level data from this diverse group of schools, the following report illuminates what one knows today about the wide range of schools providing more time for teaching and learning than the conventional schedule and calendar allow. Appended are: (1) Methodology and School Selection Criteria; (2) Characteristics of 2011-2012 Expanded-Time Schools; and (3) List of 2011-2012 Expanded-Time Schools Across the U.S. (Contains 10 figures, 8 tables, and 14 footnotes.) [Contributions provided by David Farbman and Fran O'Reilly.]