Reach

Located in the Epsilon Eridani star system in FLEETCOM Sector One, Reach was the headquarters for the UNSC, and the main supplier of military and civilian spacecraft. Originally colonized for its rich titanium deposits, Reach has mines throughout it running thousands of meters deep. HIGHCOM, FLEETCOM and the Marine Corps had headquarters on Reach, as well as many primary ONI bases, which include CASTLE Base.

CASTLE base was located on Reach underneath Mechanite Mountain. This facility is where the Spartans first began their training. The facility was destroyed after the planet's fall to the Covenant. A secret area beneath Reach's surface contained a Forerunner artifact that was highly desired by the Covenant. The fact that this artifact was so valuable to them is perhaps the main reason anyone survived Reach at all, because the Covenant were fearful of destroying it.

The Covenant discovered the location of Reach during the battle of Sigma Octanus IV. A Forerunner artifact pointed toward Reach as a location of another Forerunner artifact. Coincidentally, the Covenant attached a spy drone onto the UNSC Iroquois after the battle which allowed them to know the amount of forces around Reach. By the time of the Battle of Reach the population of the planet was 1 billion people.

Reach was defended by more than a hundred UNSC ships, including the some of the UNSC's finest vessels such as the Leviathan, the Hannibal, the UNSC Trafalgar and the Pillar of Autumn. In addition to the fleet, Reach was defended by 20 Mark V Orbital MAC satellites. Though the defenses were enormous, they couldn't hold back the Covenant onslaught.

The complete timeline of the fall of Reach: The Battle of Reach

Locations on Reach
Here are a few important places on and around Reach.

Ground Locations
 * Highland Mountains
 * CASTLE Base
 * Camp Hathcock
 * Camp Independence
 * Fairchild Field
 * HighCom Armory Omega
 * Military Reservation 01478-B
 * Military Wilderness Training Preserve
 * ODG Facility A-331
 * Olympic Tower
 * Reach Naval Academy

Orbital Locations
 * ONI Medical Facility
 * Reach Station Gamma
 * 20 Orbital Super MAC Cannons