The Argonne Leadership Computing Facility (ALCF) is a supercomputing user facility supported by the U.S. Department of Energy (DOE). The ALCF provides the computational science community with a world-class computing capability dedicated to breakthrough science and engineering. Over 5 billion core hours on Mira, ALCF’s 10-petaflops Blue Gene/Q supercomputer, are made available to peer-reviewed projects, including explorations into renewable energy, studies of the affects of global climate change, and efforts to unravel the origins of the universe. Collaborators have access to a full range of services and support. ALCF offers expertise in novel computational methods and algorithms, application porting, performance tuning and scaling, petascale system management, and high-performance analysis and visualization.