The Human Connectome Project (HCP), led by Washington University, the University of Minnesota, and Oxford University, aims to map macroscopic human brain circuits and their relationship to behavior in a large population of healthy adults. This article provides an overview of the progress made during the first half of the 5-year project, focusing on the refinement of data acquisition and analysis methods. The HCP has finalized MRI data acquisition protocols for 3T scanners and is using them to acquire high-quality data from 1200 subjects. The first quarterly release of imaging and behavioral data via the ConnectomeDB database demonstrates the commitment to making HCP datasets freely accessible. Key methodological advances include optimized pulse sequences for fMRI and diffusion MRI, improved head motion and physiological monitoring, and enhanced image reconstruction techniques. Preliminary analyses based on finalized acquisition and preprocessing protocols demonstrate the high quality of the data. The HCP datasets and associated methods and software are expected to become valuable resources for characterizing human brain connectivity, function, and their heritability and genetic underpinnings.The Human Connectome Project (HCP), led by Washington University, the University of Minnesota, and Oxford University, aims to map macroscopic human brain circuits and their relationship to behavior in a large population of healthy adults. This article provides an overview of the progress made during the first half of the 5-year project, focusing on the refinement of data acquisition and analysis methods. The HCP has finalized MRI data acquisition protocols for 3T scanners and is using them to acquire high-quality data from 1200 subjects. The first quarterly release of imaging and behavioral data via the ConnectomeDB database demonstrates the commitment to making HCP datasets freely accessible. Key methodological advances include optimized pulse sequences for fMRI and diffusion MRI, improved head motion and physiological monitoring, and enhanced image reconstruction techniques. Preliminary analyses based on finalized acquisition and preprocessing protocols demonstrate the high quality of the data. The HCP datasets and associated methods and software are expected to become valuable resources for characterizing human brain connectivity, function, and their heritability and genetic underpinnings.