In this study, we show that the southern branch of the North Anatolian Fault has been active since Late Pliocene time and that evidence of activity is supported by geological and seismological data. The southern branch of the North Anatolian Fault consists of four segments from west to east: Yenice–Gönen, Manyas–Mustafakemalpaşa, Uluabat and Bursa. These faults delimit the Bursa–Gönen Depression, with the Bandırma–Mudanya Uplift to the north and Uludağ–Sularya Uplift to the south. The Bursa–Gönen Depression includes Upper Pliocene to Recent sediments that thicken to the south, suggesting a deposition pattern under active fault control. Study of fault kinematics suggests that the Bursa–Gönen Depression started as a small pull-apart basin during Late Pliocene time, and then evolved to a large depression. The faults delimiting this depression are still active and capable of producing future earthquakes.