Ultima Macharia
From Warhammer 40k - Lexicanum
Ultima Macharia is the final world in the Macharian Crusade to have been conquered by Lord Commander Solar Macharius.
It is located in the Halo Zone, beyond the reach of the Astronomican and outside of the Segmentum Pacificus region. It was here that Macharius's troops refused to go any further, and the crusade ended. It is a testiment to the fearsome nature of Macharius, and that he managed to get this far in the name of the Emperor. It was the one thousandth planet to be conquered.