Recent research has investigated the importance of both walkable urban design and social cohesion. Social cohesion has been shown to have broad social and health benefits, and scholars have hypothesized that walkable urban design can influence cohesion, though evidence remains limited. In this work, we leveraged a data-driven approach that broke down design factors related to walkable design and investigated their impact on cohesion. We used a US-wide open urban form dataset to characterize walkable urban design, and we used an open survey dataset that measured cohesion and demographics with a total sample size of 9670 in six US cities. We leveraged partial least squared structural equation modeling for statistical analysis. We found, controlling for demographics, that land use diversity had a significant positive impact on social cohesion. We also found that physical density, social density, and transit connectedness had significant negative impacts on cohesion, though this association is largely driven by the very dense neighborhoods in cities. These findings shed light on different theories of the built environment, offering insights for designers, engineers, and policymakers interested in the social effects of the built environment.