The productivity and water quality of the Rathdrum Prairie Aquifer are inextricably linked to land-surface influences because of its unique geological composition derived from the Missoula floods, which allows for the quick entry of recharge into the aquifer. The aquifer's thick, unconsolidated Quaternary sediments provide a horizontal hydraulic conductivity that can range from 100 m/d to 3.5 km/d. The northern portion of the aquifer is primarily recharged through lake seepage, and the movement of groundwater into the southern portion of the aquifer is controlled by subsurface channels formed by bedrock ridges. To evaluate the distribution and mixing of recharge sources and the primary flowpaths within the northern Rathdrum Prairie Aquifer, an age-dating study was implemented through analysis of 40 groundwater samples for chlorofluorocarbon compounds, sulfur hexafluoride, per- and polyfluoroalkyl substances, and the stable isotopes of water. The chlorofluorocarbon compounds and sulfur hexafluoride are being used as a traditional, young water age-dating technique to evaluate dominant recharge sources and mixing of these sources as the groundwater moves into the channel connections. The per- and polyfluoroalkyl substances are being evaluated as a possible age-dating technique because of their environmental persistence and temporal differences of entry into the hydrologic cycle. The stable isotopes of water are assisting with the discrimination of recharge sources and their mixing patterns. The goal of the study is to refine our understanding of aquifer dynamics for the northern portion of the aquifer and its contribution to the larger Spokane Valley-Rathdrum Prairie Aquifer. Our improved understanding of the aquifer will assist with the new groundwater modeling effort that is being undertaken to improve wellhead protection and analysis of future water demands on this sole-source aquifer.