Inner Colonies (Earth-5875)

The Inner Colonies were the first planets colonized by the Unified Earth Government during Domus Diaspora in the 2200s. They are the closest to Earth and the Sol system, and as the first planets became home to the brightest minds of Earth. They are also known as the core worlds collectively.

History
The Inner Colonies were made of 115 planets located near the Sol system, colonized during the initial expansion of the Unified Earth Government during Domus Diaspora, from 2212 to 2390, which started with the launch of the colony ship Odyssey and its landing on Reach. From there on, the colonization of Epsilon Eridani and other nearby systems commenced. Duo to the initial highly expensive nature of slipspace travel, those who became colonists had to pass through rigorous sets of training and exercises to prove apt enough for travel. With time, such idea grew that the Inner Colonies were home to the elite of humanity: the brightest and best.

When the UNSC started expanding even more with the Outer Colonies, the Inner Colonies effectively became home to the established social norms and basis for all of the Unified Earth Government. During the Secession, the Inner Colonies became a source of targets for Insurrectionist attacks, with terrorism and piracy threatening its citizens. The UNSC acted against these attacks to restore order in UEG, leading to the SPARTAN-II Program.

Through the First Contact War, most ships in the Inner Colonies were re-purposed to defend the Outer Colonies, which were facing the attack of the Covenant much more violently, one of them being the UNSC Pillar of Autumn, which was later sent back to the Inner Colonies. By the end of the war, most Inner Colonies also started being attacked by the Covenant, with the last straw being considered the Fall of Reach.