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.
The city was one of the first population centers on Reach to be attacked by the Covenant in the summer of 2552. 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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