Crescentia is a crescent shaped artificial satellite that orbits around the planet Montressor, from Montressor's surface, Crescentia resembles a crescent moon. It serves as the worlds spaceport, and thus as a centre of trade. It is here that Jim Hawkins, and the rest of the Doppler Expedition boarded the RLS Legacy.

Clarke's Nebula and the Royal Navy academy, Port Ivy, are located west of Crescentia.