A computer-implemented method for identifying a merchant location for a merchant based on one or more payment account transactions performed at the merchant, the method comprising: accessing multiple router records, each router record generated by a portable communication device and assigned to one of multiple cells of a grid structure indicative of geographic location, each of the multiple cells associated with signal strengths of routers (116a-c), and each router record including a temporal indicator specific to one or more signal strengths recognized by the portable communication device at a time and date indicated by the temporal indicator, each signal strength defining a strength, at the portable communication device, of a signal of a corresponding one of the routers (116a-c); for each of the multiple router records, searching, by a computing device, for a match between the router record and at least one of multiple transaction records associated with the merchant, each of the multiple transaction records including at least a temporal indicator indicative of a time and a date at which a transaction represented by the transaction record was initiated, the match based on a consistency between the temporal indicator of the router record and the temporal indicator of the at least one of the multiple transaction records; based on the searching, for each one of the multiple cells of the grid structure, counting a number of matches between one or more router records assigned to the one of the multiple cells of the grid structure and ones of the multiple transaction records associated with the merchant; and reporting one or more of the multiple cells as a location associated with the merchant, based on the counted number of matching router records assigned to said one or more of the multiple cells exceeding a predetermined threshold. accessing multiple router records, each router record generated by a portable communication device and assigned to one of multiple cells of a grid structure indicative of geographic location, each of the multiple cells associated with signal strengths of routers (116a-c), and each router record including a temporal indicator specific to one or more signal strengths recognized by the portable communication device at a time and date indicated by the temporal indicator, each signal strength defining a strength, at the portable communication device, of a signal of a corresponding one of the routers (116a-c); for each of the multiple router records, searching, by a computing device, for a match between the router record and at least one of multiple transaction records associated with the merchant, each of the multiple transaction records including at least a temporal indicator indicative of a time and a date at which a transaction represented by the transaction record was initiated, the match based on a consistency between the temporal indicator of the router record and the temporal indicator of the at least one of the multiple transaction records; based on the searching, for each one of the multiple cells of the grid structure, counting a number of matches between one or more router records assigned to the one of the multiple cells of the grid structure and ones of the multiple transaction records associated with the merchant; and reporting one or more of the multiple cells as a location associated with the merchant, based on the counted number of matching router records assigned to said one or more of the multiple cells exceeding a predetermined threshold.