The coronavirus disease 2019 (COVID-19) pandemic has disproportionately impacted Black nursing home (NH) residents. Alzheimer's Disease and Related Dementias (ADRD) may exacerbate disparities, however little empirical evidence exists on the degree to which race and ADRD intersect to impact COVID-19-related outcomes. We conducted a cohort study (April-December 2020) leveraging electronic health records from 12 United States NH corporations. We used parametric g-formula to obtain standardized estimates of incident COVID-19 infection and 30-day COVID-19-associated hospitalization or death by race, both overall and within strata of ADRD status. The cohort comprised 127,913 resident-episodes, including 15,379 incident COVID-19 infections, 1,522 deaths, and 2,548 hospitalizations. Black residents were more likely than White residents to experience incident COVID-19 and subsequent hospitalization, but not more likely to subsequently die. Disparities in hospitalization and a combined endpoint of hospitalization or death were more pronounced among residents with ADRD compared to residents without ADRD. These results suggest the presence of disparities in COVID-19 outcomes by race and provide evidence that ADRD status may exacerbate racial disparities in COVID-19 outcomes among nursing home residents. Our findings offer valuable insights for current and future preparedness efforts in NHs in the United States and countries with similarly under-resourced long-term care settings.