This data release presents tabular data used and analytical water-level modeling files generated as part of a U.S. Geological Survey study, done in cooperation with the Confederated Tribes of the Umatilla Indian Reservation, to evaluate water-level change from a multiple-well aquifer test in well 422 on the Umatilla Indian Reservation near Mission, Oregon. Water-level, pumping, and barometric-pressure data collected during February 1, 2016–April 18, 2016 were used within the accompanying water-level modeling files to estimate drawdown in observation and background wells from the aquifer test. Water-level models were created within Excel spreadsheets using an Excel Add-in called SeriesSEE (Halford and others, 2012). Each Excel based water-level model file is attached within a .zip folder. The raw water levels, barometric presssure, and pumping rates from the multiple-well aquifer test are included within the child item. The raw and simplified tabular data contains water levels from 12 wells, barometric pressure from two different sites, and pumpage data in .csv file format. Reference cited: Halford, K., Garcia, C.A., Fenelon, J., and Mirus, B., 2012, Advanced methods for modeling water-levels and estimating drawdowns with SeriesSEE, an Excel add-In, (ver. 1.2, July, 2016): U.S. Geological Survey Techniques and Methods 4–F4, 28 p., http://dx.doi.org/10.3133/tm4F4.