Abstract: The purpose of this Coastal and Hydraulics Engineering technical note (CHETN) is to summarize a portion of recently published work (Young, Kress, et al. 2022) that used archival Automatic Identification System (AIS) data to measure the commercial vessel traffic connected to Puerto Rican and US Virgin Island (USVI) port areas from January 2015 to June 2020. Vessel movement derived from AIS was aggregated to construct a network that measured the port-to-port connectivity for all ports in the network and the interconnectivity of traffic between those ports. AIS data provided a description of vessel movement and the identification of specific vessel classes. Metrics such as interconnectedness can be used in conjunction with standard US Army Corps of Engineers (USACE) metrics describing waterway utilization, which traditionally have included total tonnage and specific commodity tonnage. The ability to consider the self-selected vessel-type broadcast via AIS, as well as dominant commodity type and tonnage reported through statistical publications, provides a fuller and more accurate description of waterway capacity utilization. This knowledge, along with port-to-port interconnectedness, reveals potential redundancies between ports, robustness across supply chains, and the impacts of seasonality, thereby allowing the USACE to expand its understanding of maritime supply-chain resilience.