Sidescan sonar provides a map of the seafloor that has greatly improved the understanding of depositional processes on modern deep-sea fans (e.g. Mutti and Normark 1991). Here, we present a sidescan-sonar mosaic from the eastern Gulf of Mexico that images the distal reaches of a channel on the Mississippi Fan and the deposits associated with it (Fig. 41.1). This area is one of several deep-sea fan systems that had not previously been imaged by high-resolution sidescan systems. The mosaic highlights the complexity of the spatial relationships of channels and deposits at ends of channels on this large, modern, passive-margin deep-sea fan (Figs 41.2 and 41.3).