In this paper, we propose a novel application of digital watermarking, determination of recording locations. This application enables us to determine the seat location in an auditorium where a recording was made. Precisely measured synchronization positions of the spread-spectrum watermarks are used for the determination. To avoid use of mismeasured synchronization positions, the algorithm discards synchronization positions with the corresponding normalized correlation values below a threshold. The experiments with our implementation resulted in accurate determinations; almost all of the locations can be determined within the error of 0.5 m. These experimental results successfully show the potential applicability of our application.