The purpose of this study is to develop and test a local measure of walkability in San Francisco County and evaluate walkability by race, ethnicity, and educational attainment at the census block group level. We used data collected as part of the 2019–2020 Bay Area Young Adult Health Study, wherein we conducted audits of 1525 randomly selected census blocks to assess domains, such as aesthetics, access to amenities, street safety, and topography, which we then imputed to the remaining blocks in the city for overall coverage. We linked the walkability index to 2015–2019 American Community Survey Data aggregating walkability to the block group level. We performed a geographically weighted regression to measure associations between walkability, race/ethnicity, and educational attainment and found significant negative associations between walkability and the percentage of non-Hispanic Black residents in specific neighborhoods and non-Hispanic Asian residents in all neighborhoods. We also found significant positive associations between the percentage of residents with a bachelor’s or higher degree and walkability. Inequities in walkability across neighborhoods in San Francisco County largely mirrored sociodemographic inequities. Our approach to constructing a walkability index points to a relatively efficient means of estimating fine-scale neighborhood characteristics in urban areas, and our findings suggest that investments in neighborhood infrastructure may positively impact walkability and address broader inequity concerns.