The U.S. Geological Survey (USGS), in cooperation with the Connecticut Department of Energy and Environmental Protection and the Connecticut Department of Transportation, calculated select streamflow statistics and basin characteristics. This U.S. Geological Survey (USGS) data release provides select streamflow statistics and basin characteristics for 118 streamgages in Connecticut and adjacent states compiled using data through water year 2022. A subset of the data from select streamgages with minimally altered flow conditions was used in the development of statewide regression equations to estimate: 1-, 5-, 10-, 25-, 50-, 75-, 90-, 99-percent flow durations; 7-day, 10-year low-flow frequency (7Q10) and 30-day, 2-year low-flow frequency (30Q2); mean flow, spring mean flow, and harmonic mean flow; and monthly and seasonal flow durations ranging from 1- to 99-percent for six bioperiods ⸺ salmonid spawning (November), overwinter (December–February), habitat forming (March-April), clupeid spawning (May), resident spawning (June), and rearing and growth (July–October). The data used in this study were compiled to help provide federal and state governments with the information needed to manage their water resources. This data release contains (1) data files in comma-separated values (.CSV) format of the streamflow statistics and basin characteristics for 118 streamgages, and (2) the USGS Weighted Multiple-Linear Regression (WREG, version 3.0) input and output data files in text format for four sets of regressions (n-day frequency, flow durations, bioperiod flow durations, and mean flows). The WREG input and output files for 47 statewide regression equations are in zipped folders.