From Halopedia, the Halo wiki
Manassas was a city in the state of Alföld of the Ütközet province on the planet Reach. It was among the three largest cities on Reach, the other two being Ezhtergom and Quezon. Just outside the city were rugged mountains. One of Reach's spaceports, the Manassas Spaceport, was located in the city. Manassas was also home to one of Reach's nine space elevators.
Fall of Reach
The city was attacked by the Covenant during the final day of the Fall of Reach on August 30, 2552 when a massive contingent of Covenant forces led by the Supreme Commander Thel 'Vadamee and a combined fleet of 315 vessels arrived over Reach. The Covenant assault on the city was led by a flotilla of at least one CCS-class battlecruiser and SDV-class heavy corvette. ODST air assault troopers were deployed to harass Covenant forces in the mountains outside the city. One of the planet's civilian evacuation stations was located in Manassas, but it was apparently destroyed by the Covenant prior to the glassing of the entire globe.
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