This paper studies knowledge flows, as measured by patent citations, between pairs of US cities. It adds to the knowledge spillover literature by quantifying the distance within which knowledge flows are localized in the US. This analysis further allows us to estimate the knowledge absorptive capacities of cities. Differences in absorptive capacities are explained by local economic conditions such as the entrepreneurial, innovative, and industrial structures of the cities. Given the limited research on knowledge absorption beyond the firm level, the paper significantly contributes to that literature.