The Hellas Basin Rim region is defined by the northern escarpment of the Hellas Basin proper, situated at a relatively constant elevation of 1000 m above the Martian datum. This forms an approximately triangular region of points south of a line running between the points (32S, 50E), (18S, 62E), and (30S, 82E). The Hellas Basin Rim has 17 mapped bedrock plains.
This region has been interpreted to be a sedimentary apron built from the transport of materials off the extremely high terrain north of the Hellas Basin into Hellas proper, with later resurfacing by volcanism. (Salese et al. 2016).