Wet deposition of Per- and poly-fluoroalkyl substances (PFAS) is widespread and a pathway for contamination of both land and water systems. Source attribution for wet deposited PFAS is challenging, in part because of the complexity of atmospheric transport of PFAS and the event-based nature of wet deposition. To address this challenge, we have developed a novel approach to directly investigate the impact of air-mass history on PFAS composition. This approach uses the Stochastic Time-Inverted Lagrangian Transport (STILT) Model to track the air masses corresponding to wet deposition periods backward in time for a specific sampling period. Back trajectory footprints are then combined with PFAS concentration data over a large number of samples using the concentration-weighted trajectory approach to identify possible hotspots associated with higher PFAS. Here, we apply this approach to two years of PFAS concentration observations from five National Atmospheric Deposition Program-National Trends Network (NADP-NTN) sites in Minnesota and Michigan.This analysis enables investigation of how source region varies for different PFAS species, seasons, and rain types, providing new insights into the sources of and controls on PFAS in wet deposition.