Aftermost
/ˈæftərməʊst/
Definition 1 of 1
Pro Tip 1/3Physical Locations
Often used to describe the furthest position of something within a physical space. 
The tourists moved to the aftermost deck to get a clearer view of the horizon.
Pro Tip 2/3Not Always Last
'Aftermost' implies far back, but not necessarily the final in a sequence. 
He chose the aftermost row in the auditorium, but three rows were still behind him.
Pro Tip 3/3Often Nautical
Commonly used in nautical contexts like on ships, referring to the part nearest the stern. 
The captain's quarters are traditionally located in the aftermost section of the vessel.