阿留申海沟是位于太平洋北侧的一条海沟，呈近似东西走向的向南凸出的弧形，西接千岛-堪察加海沟的北端，东至阿拉斯加湾，绵延3,400千米。它和邻近的相同走向的阿留申群岛构成太平洋西侧的岛弧-海沟系的最北部分，并成为太平洋板块和北美洲板块的分界。这段分界是一个消减带，太平洋板块在此以平均45度的俯冲角向北消减于北美洲板块之下。阿留申海沟的最深点，经测量，为7,679米。

阿留申海沟西段南边不远就是著名的天皇海山。由于海底扩张，在可以预计的将来，天皇海山将陆续在阿留申海沟处俯冲、消失。

根据现时太平洋板块移动方向显示，如果未来地球发生黎克特制规模10地震的话，震央有可能会在千岛海沟或阿留申海沟附近海域。

The Aleutian Trench (or Aleutian Trough) is an oceanic trench along a convergent plate boundary which runs along the southern coastline of Alaska and the Aleutian islands. The trench extends for 3,400 km from a triple junction in the west with the Ulakhan Fault and the northern end of the Kuril-Kamchatka Trench, to a junction with the northern end of the Queen C******te Fault system in the east. It is classified as a "marginal trench" in the east as it runs along the margin of the continent. The subduction along the trench gives rise to the Aleutian arc, a volcanic island arc, where it runs through the open sea west of the Alaska Peninsula. As a convergent plate boundary, the trench forms part of the boundary between two tectonic plates. Here, the Pacific Plate is being subducted under the North American Plate at a dip angle of nearly 45 degrees. The rate of closure is ~3in. (8 cm) per year.