Heinlein is Luna's great colony agglomeration: Armstrong Base, Harriman Dome (with Wyldside g-mod culture), Lunacent, Melange facilities, Starport Kaguya, Tranquility Home, and more.

Named in setting materials alongside the Treaty of Heinlein, it is the political and industrial heart of the Moon after the War. Melange Mining's dominance, Loonie identity, and corp labs (including HB and Jinteki presence) make it a mirror of New Angeles—colder, lower-g, more fragile life support.

SotB Ch.4 covers districts; Loonie PCs often hail from here.