Abstract Background To highlight geographic differences and the socio-structural determinants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test positivity within Los Angeles County (LAC). Methods A geographic information system was used to integrate, map, and analyze SARS-CoV-2 testing data reported by the LAC Department of Public Health and data from the American Community Survey. Structural determinants included race/ethnicity, poverty, insurance status, education, and population and household density. We examined which factors were associated with positivity rates, using a 5% test positivity threshold, with spatial analysis and spatial regression. Results Between 1 March and 30 June 2020 there were 843 440 SARS-CoV-2 tests and 86 383 diagnoses reported, for an overall positivity rate of 10.2% within the study area. Communities with high proportions of Latino/a residents, those living below the federal poverty line, and with high household densities had higher crude positivity rates. Age- adjusted diagnosis rates were significantly associated with the proportion of Latino/as, individuals living below the poverty line, and population and household density. Conclusions There are significant local variations in test positivity within LAC and several socio-structural determinants contribute to ongoing disparities. Public health interventions, beyond shelter in place, are needed to address and target such disparities.