The Human Connectome Project consortium led by Washington University, University of Minnesota, and Oxford University is undertaking a systematic effort to map macroscopic human brain circuits and their relationship to behavior in a large population of healthy adults. This overview article focuses on progress made during the first half of the 5-year project in refining the methods for data acquisition and analysis. Preliminary analyses based on a finalized set of acquisition and preprocessing protocols demonstrate the exceptionally high quality of the data from each modality. The first quarterly release of imaging and behavioral data via the ConnectomeDB database demonstrates the commitment to making HCP datasets freely accessible. Altogether, the progress to date provides grounds for optimism that the HCP datasets and associated methods and software will become increasingly valuable resources for characterizing human brain connectivity and function, their relationship to behavior, and their heritability and genetic underpinnings. •The Human Connectome Project (HCP) will study brain connectivity in healthy adults.•Data acquisition: multiple imaging modalities, plus behavioral, and genetic data.•Imaging modalities: diffusion MRI, resting-fMRI, task-fMRI, and MEG/EEG.•Extensive refinement and optimization efforts are currently underway.•Data will be made freely available and will enable flexible data mining.