This U.S. Geological Survey (USGS) data release contains the code, data, executables, and other information necessary to run the application Unit Flows in Networks of Channels (UFINCH). The UFINCH application is a computer code that utilizes the geospatial stream connectivity and catchment geometry described in National Hydrography Dataset Plus value added attributes (NHDPlus Version 2) to simulate unit (15-minute) flows in networks of channels, generally by use of daily flows at the most downstream stream segment in a basin at which a USGS streamgage is located. Preliminary testing indicates that UFINCH may be most applicable for simulating unregulated, non-estuarial, flows in basins as large as 3,000 square miles in area. Streamgage information is available for the continental United States, Hawaii, Puerto Rico, and the Virgin Islands. Alaska is not included in this streamgage dataset. The contents of this data release support the following publication: Holtschlag, D.J., 2016, UFINCH-A method for simulating unit and daily flows in networks of channels described by NHDPlus using continuous flow data at U.S. Geological Survey streamgages: U.S. Geological Survey Scientific Investigations Report 2016-5074, 17 p., https://doi.org/10.3133/sir20165074.