To achieve the DES science goals, the DES Collaboration designed, built, and utilized the Dark Energy Camera (DECam), a 570 megapixel camera with a 3deg^2^ field of view installed at the prime focus of the 4m Blanco telescope at Cerro Tololo Inter-American Observatory (CTIO) in northern Chile. The first major release of processed DES data, DES DR1 (II/357), encompassed data products derived from the wide-area and the supernova surveys taken in the first three years of science operations (2013-August -- 2016-February). Here we present the content, validation, and data access services for the second public DES data release, DES DR2. DES DR2 comprises coadded images of size 0.534deg^2^ and source catalogs, as well as calibrated single-epoch CCD images, from the processing of all six years of DES wide-area survey observations and all five years of DES supernova survey observations. DES DR2 contains roughly 18TB of coadd images and 3TB of tables. All DES DR1 data have been reprocessed as input into DES DR2. DES was scheduled to observe for 760 distinct full or half nights between 2013 August 15 and 2019 January 9. The DES DR2 coadd images and catalogs are derived from a subset of the wide-area component of DES and include exposures collected during 681 distinct nights. See Section 2. All magnitudes quoted in the text are in the AB system, and all astronomical coordinates are provided in the Gaia-CRF2 reference frame. All quoted uncertainties are 1{sigma} (roughly 68% confidence interval) unless indicated otherwise.

This project used public archival data from the Dark Energy Survey (DES). Funding for the DES Projects has been provided by the U.S. Department of Energy, the U.S. National Science Foundation, the Ministry of Science and Education of Spain, the Science and Technology Facilities Council of the United Kingdom, the Higher Education Funding Council for England, the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign, the Kavli Institute of Cosmological Physics at the University of Chicago, the Center for Cosmology and Astro-Particle Physics at the Ohio State University, the Mitchell Institute for Fundamental Physics and Astronomy at Texas A&M University, Financiadora de Estudos e Projetos, Fundacao Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico and the Ministerio da Ciencia, Tecnologia e Inovacao, the Deutsche Forschungsgemeinschaft and the Collaborating Institutions in the Dark Energy Survey. The Collaborating Institutions are Argonne National Laboratory, the University of California at Santa Cruz, the University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas-Madrid, the University of Chicago, University College London, the DES-Brazil Consortium, the University of Edinburgh, the Eidgenossische Technische Hochschule (ETH) Zurich, Fermi National Accelerator Laboratory, the University of Illinois at Urbana-Champaign, the Institut de Ciencies de l'Espai (IEEC/CSIC), the Institut de Fisica d'Altes Energies, Lawrence Berkeley National Laboratory, the Ludwig-Maximilians Universitat Munchen and the associated Excellence Cluster Universe, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, The Ohio State University, the OzDES Membership Consortium, the University of Pennsylvania, the University of Portsmouth, SLAC National Accelerator Laboratory, Stanford University, the University of Sussex, and Texas A&M University. Based in part on observations at Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, which is operated by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. See http://des.ncsa.illinois.edu/thanks for the TeX version.