This chapter focuses on the Oriente and Swan Fracture Zones which form the active plate boundary of the eastern and western Cayman Trough, respectively. The Cayman Trough is a seismically active transform plate boundary that extends 1600 km eastward from the Gulf of Honduras to the Windward Passage and likely to the Puerto Rico Trench. Ewing, J., et al. conducted a seismic refraction survey of the Cayman Trough region which included seven seismic refraction profiles across the Cayman Trough. T. L. Holcombe and G. F. Sharman proposed a post-Miocene evolution for the Cayman Trough based on the variation in orientation of spreading fabric and magnetic lineations. The western portion of the Cayman Trough lies west of 83°W and includes the Swan Fracture Zone. One major submarine canyon has been traced in the western Cayman Trough.