By inspecting continuous Trinet waveform data, we find 42 foreshocks in the 20-hour period preceding the 1999 Hector Mine earthquake, a substantial increase from the 18 foreshocks in the catalog. We apply waveform cross-correlation and the double-difference method to locate these events. Despite low signal-to-noise ratio data for many of the uncataloged foreshocks, correlation-based arrival time measurements are sufficient to locate all but three of these events, with location uncertainties from ~100 m to 2 km. We find that the foreshocks fall on a different plane than the initial subevent of the mainshock, and that the foreshocks spread out over the plane with time during the sequence as the time of the mainshock approaches.