Local and regional food supply chains are gaining increasing support from public and private sectors for their contributions to economic development and promoting sustainability. However, the impacts of regionalization are not well understood. We employ a spatial-temporal model of production and transportation to evaluate the supply chain outcomes of a decade-long process of food regionalization for fresh broccoli in the eastern United States (US). Our results indicate that eastern broccoli supply chains displaced products sourced from the western US and met over 15% of the annual demand in eastern markets in 2017. We find that total broccoli supply chain costs and food miles increased in the period 2007–2017. Nevertheless, eastern-grown broccoli has contributed to reducing regional food miles in the eastern region (from 365 miles in 2007 to 255 miles in 2017) and experienced only modest increases in supply chains costs (a 3.4% increase, compared to a 16.5% increase for broccoli shipped from western US) during the same period. Our results provide valuable information for policymakers and the fresh produce industry interested in promoting regional food supply chains.