The northern edge of the Gulf Stream off Cape Hatteras, North Carolina was located in 155 AVHRR-derived maps of sea surface temperature (SST) using five different methods. One method was subjective location of the northern edge by an analyst; the other four involved objective location of the edge by computer using various statistics of the SST field. Specifically, the quantities considered were: maximum SST gradient (calculated over a 3 × 3 pixel box), maximum SST (on a pixel-by-pixel basis), maximum variance (calculated over a 7 × 7 pixel box), and change in the skewness of the SST distribution (calculated over a 5 × 5 pixel box). The resulting locations were compared with the location of the 15°C isotherm at 200 m (T15) determined from inverted echo sounders (IESs) moored on the sea floor. The best method, which yielded the smallest rms difference from the IES-derived T15, was the subjective one; the surface front was located 9.0 km shoreward of T15 with a rms difference of 14.3 km. The best ob... Abstract The northern edge of the Gulf Stream off Cape Hatteras, North Carolina was located in 155 AVHRR-derived maps of sea surface temperature (SST) using five different methods. One method was subjective location of the northern edge by an analyst; the other four involved objective location of the edge by computer using various statistics of the SST field. Specifically, the quantities considered were: maximum SST gradient (calculated over a 3 × 3 pixel box), maximum SST (on a pixel-by-pixel basis), maximum variance (calculated over a 7 × 7 pixel box), and change in the skewness of the SST distribution (calculated over a 5 × 5 pixel box). The resulting locations were compared with the location of the 15°C isotherm at 200 m (T15) determined from inverted echo sounders (IESs) moored on the sea floor. The best method, which yielded the smallest rms difference from the IES-derived T15, was the subjective one; the surface front was located 9.0 km shoreward of T15 with a rms difference of 14.3 km. The best ob...