Stuff

By 2390 CE, with the founding of 210 colony worlds, the Inner Colonies were formally established. Ranging from worlds with human settlements to mining or industrial colonies with no human presence, these diverse colonies were governed by the Colonial Administration, a group that answered to the United Earth Government but had its own military fleet, although not a force as powerful or advanced as the UNSC fleet.

The following century was a boom time for humanity. The Inner Colonies rapidly grew in population and importance. By 2490 CE, human space encompassed over 800 planets. They ranged from centers of industry and technology to pioneer settlements that could barely sustain 10,000 colonists.

Halo: Encyclopedia