Posttranslational modifications of protein cysteine thiols play a significant role in redox regulation and the pathogenesis of human diseases. However, the cellular redox landscape in terms of quantitative, site-specific occupancies of thiol modifications at the proteome level, especially under physiological conditions, is still largely uncharacterized. Herein, we report the site occupancies of both S-glutathionylation (SSG) and total reversible thiol oxidation (total oxidation) in RAW 264.7 macrophage cells under basal conditions. The occupancies of thiol modifications for ~4,000 cysteine sites were quantified, which revealed a mean site occupancy of 4.0% for SSG and 11.9% for total oxidation, respectively. Correlations between site occupancies and structural features such as pKa, relative residue surface accessibility, and hydrophobicity were observed. Proteome-wide site occupancy analysis also revealed a strong subcellular compartmentalization in thiol redox status, where the average occupancies of SSG and total oxidation in distinct compartments correlate well with the redox potentials of respective organelles.