FEWSION is mapping the supply chains and network structures of US cities. FEWSION™ has built the first complete empirical description of the U.S. food, energy, and water system (the FEW Nexus) so that every citizen and policymaker in the U.S. can see where their food, energy, and water come from. The data product, real-world applications, and key science results will be reviewed in this short lecture. For background details see the website at https://fewsion.us/.