Geological Chronicle
Rima Mairan is a lunar graben structure spanning 120.51 kilometers in length across the lunar basalt crust. Formed by structural faulting and crustal extension, the trench cuts through terrain within the Rümker quadrangle (LAC-23).
Officially cataloged by the International Astronomical Union at selenographic coordinates 38.2789° latitude and -46.8273° longitude, the rille designation notes: Named from nearby crater.