This dataset was compiled to summarize discharge measurements from several published groundwater and surface-water studies in the Ozarks of southern Missouri and northern Arkansas. The discharge measurements were part of numerous USGS studies to assess interaction between streams and groundwater aquifers. A gaining stream is described as a surface-water stream that gains water from the groundwater aquifer and a losing stream is described as a surface-water stream that loses water to the groundwater aquifer. This product is intended to be used in surface-water and groundwater investigations assessing water quantity, quality, and availability. The product includes flow-line data digitized along National Hydrography Dataset (NHD) flow lines and between adjacent discharge measurements (that is, seepage flow-line reaches). The seepage flow-line reaches include a calculation to determine if discharge between the upstream and downstream measurement points is increasing (termed "Gain"), decreasing (termed "Lose"), or remaining neutral if the net change in discharge is not greater than the error (termed "Neutral"). Original seepage-run studies included estimates of discharge measurement error and some studies estimated error along the seepage flow-line reach; however, because of the variety of ways that error was calculated in the original studies and to create a consistent error estimation for the entire spatial dataset, error was assumed to be 10% of the largest discharge measurement along the seepage flow-line reach. Contribution of discharge from tributaries and springs that emerge before flowing into the stream was taken into account, such that the net change in discharge between the upstream and downstream measurement points was calculated as the downstream discharge minus the total discharge from the upstream measurement point and from tributaries/springs. This calculation quantifies the amount of groundwater flow entering the stream as diffuse or point discharge, presumably into the stream bed. The net change in discharge was additionally calculated as the downstream discharge minus the total discharge from both the upstream measurement point and from surface-water tributaries only. This calculation quantifies the amount of groundwater entering the stream as discrete springs adjacent to the stream and diffuse or point groundwater flow directly to the stream bed. A positive net change in discharge results in the seepage flow-line reach gaining discharge (that is, "Gain") and a negative net change in discharge results in the seepage flow-line reach losing discharge (that is, "Lose"). Designations of gaining, losing, or neutral streams may vary between this dataset and the original studies because of differences in how error was calculated and other interpretations made in the seepage-run studies. Users are encouraged to refer to the source reports for further details about data collection methods, results, and interpretations of stream-aquifer dynamics. This spatial dataset is meant to provide a digital compilation of seepage studies in the Ozarks and to create a consistent dataset across studies completed over 24 years.