Digital flood-inundation maps for a 6.7-mile reach of Joachim Creek at De Soto, Missouri, were created by the U.S. Geological Survey (USGS) in cooperation with the city of De Soto, Missouri, and Jefferson County, Missouri. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgage 07019500 on Joachim Creek at De Soto, Missouri. Near-real-time stages at this streamgage may be obtained on the Internet from the USGS National Water Information System at http://waterdata.usgs.gov/ or the National Weather Service Advanced Hydrologic Prediction Service at http:/water.weather.gov/ahps/, which also forecasts flood hydrographs at this site. Flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model. The model was calibrated using current stage-discharge measurements at the USGS streamgage 07019500 on Joachim Creek at De Soto, Missouri, and documented high-water marks from the flood of April 18, 2013. The hydraulic model was then used to compute 10 water-surface profiles for flood stages at 1-foot (ft) intervals referenced to the streamgage datum and ranging from 8 ft, or near bankfull, to 17 ft, which exceeds the stage corresponding to the 0.2 percent annual exceedance probability flood (500-yr recurrence interval). The simulated water-surface profiles were then combined with a Geographic Information System digital elevation model (derived from light detection and ranging [lidar] data having a 1.0-ft vertical accuracy and 3.28-ft horizontal resolution) to delineate the area flooded at each water level. The availability of these maps, along with Internet information regarding current stage from the USGS streamgage and forecasted high-flow stages from the NWS, will provide emergency management personnel and residents with information that is critical for flood response activities such as evacuations and road closures, as well as for post flood recovery efforts.