The U.S. National Oceanic and Atmospheric Administration’s (NOAA’s) Ocean Noise Reference Station (NRS) Network was established in partnership with the National Park Service (NPS) to document baseline levels and multi-year trends in ocean ambient sound in 12 discrete environments throughout the U.S. Exclusive Economic Zone (EEZ). Using time-series data collected within four National Marine Sanctuaries (NMS), two National Parks, and six other habitats throughout the U.S. EEZ, the NRS network provides data to compare long-term changes and trends in the low-frequency underwater ambient sound field. Monitoring these biological areas of interest is of high importance; these environments are home to a variety of endangered marine animals but are at the same time exposed to increased human use including recreational/commercial shipping and fishing as well as renewable energy efforts. Establishment and continuation of the NRS Network has been funded by the NMFS Ocean Acoustics Program, Pacific Marine Environmental Laboratory (OAR), the Office of National Marine Sanctuaries (NOS), all NMFS Science Centers, and the National Park Service. See https://www.pmel.noaa.gov/acoustics/noaanps-ocean-noise-reference-station-network.