The U.S. Geological Survey maintains a program of water-quality studies in San Francisco Bay (CA) that began in 1969. This U.S.G.S. Data Release archives and makes available all measurements from 2016-2021, and is a continuation of the previously published 1969-2015 dataset (Cloern and Schraga, 2016; Schraga and Cloern, 2017). Water-quality constituent measurements include salinity, temperature, light attenuation coefficient, and concentrations of chlorophyll-a, dissolved oxygen, suspended particulate matter, and dissolved inorganic nutrients (nitrate, nitrite, ammonium, phosphate and silicate). The sampling was conducted at least monthly at 37 fixed sampling locations along a 145-km transect from lower South San...