This ecological study examines county-level associations between ozone exposure and chronic health outcomes—adult asthma, chronic obstructive pulmonary disease (COPD), and coronary heart disease (CHD)—across the United States from 2020 to 2023. Using integrated datasets from the EPA, CDC PLACES, and the U.S. Census, we evaluated both short-term ozone indicators (days exceeding 70 ppb) and annual average ozone concentrations. Spatial analysis revealed substantial geographic mismatch between high-ozone regions, largely in the Western United States, and high chronic disease burden, concentrated in the Southeast and Appalachia. Multivariable ordinary least squares (OLS) regression models showed that socioeconomic and demographic factors—particularly median income and racial/ethnic composition—were strong and consistent predictors of all three chronic health outcomes. In contrast, ozone indicators displayed weak or nonsignificant associations with disease prevalence at the county level. Negative coefficients observed for COPD and CHD likely reflect spatial confounding rather than protective effects. These findings highlight the limitations of ecological, annual-summary designs in capturing pollution–health relationships and emphasize the dominant role of social determinants in shaping chronic disease patterns. Future work incorporating higher temporal resolution or individual-level data may better characterize ozone’s health impacts.