This data release includes monitoring data collected by the U.S. Geological Survey (USGS) Humboldt Bay Water Quality and Salt Marsh Monitoring Project. The datasets include continuous water levels collected at a 6-minute time step collected in two study marshes (Mad River and Hookton). Surface deposition, elevation changes and carbon storage (in marsh edge environments) measured in five USGS study marshes (Mad River, Manila, Jacoby, White and Hookton). The monitoring data presented in this data release represent fundamental datasets needed to manage blue carbon stocks, assess marsh vulnerability, inform sea-level rise (SLR) adaptation planning, and build coastal resiliency to climate change in Humboldt Bay, CA Additional documentation is provided in a companion report. Curtis et al, 2022 A Summary of Water-Quality and Salt Marsh Monitoring during Water Years 2013 to 2019, Humboldt Bay, CA.