The spreading ridge geomorphic feature layer represents the spatial extent of the spreading ridges of the worlds oceans based on interpretation of the SRTM30 plus v7 global bathymetry model. The layer is one of the 25 layers that make up the global seafloor geomorphic features map (Harris et.al. 2014). Mid-ocean spreading ridges are ???the linked major mid-oceanic mountain systems of global extent??? (IHO, 2008). Spreading ridges are distinguished from other ridges in this study (see definition of ridges below). They were mapped by hand based on their appearance as ridge-like features that coincide with the youngest ocean crust as mapped by M??ller et al. (1997) in their ???EarthByte??? digital age grid of the ocean floor. Spreading ridges that were not visible in the SRTM30_PLUS bathymetry (100 m contours) were not included in our interpretation, but there is otherwise no size limitation on spreading ridges.