Resolving the spatial distribution of the human proteome at a subcellular level greatly increases our understanding of human biology and disease. Here, we present a comprehensive image-based map of the subcellular protein distribution, the Cell Atlas, built by integrating transcriptomics and antibody-based immunofluorescence microscopy with validation by mass spectrometry. Mapping the in situ localization of 12,003 human proteins at a single-cell level to 30 subcellular structures enabled the definition of 13 major organelle proteomes. Exploration of the proteomes reveals single-cell variations of abundance or spatial distribution, and localization of approximately half of the proteins to multiple compartments. This subcellular map can be used to refine existing protein-protein interaction networks and provides an important resource to deconvolute the highly complex architecture of the human cell.