ONI Alpha Site (location)

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This article is about the ONI facility. For other uses, see Alpha Site (disambiguation).
ONI Alpha Site
Alphabase new 1.png
Facility information


Sector 10, New Mombasa, Kenya, Earth


ONI EAP headquarters[1]
Data aggregator for nearby Forerunner structure[1]
Historical information

In use:

2552: Battle of Mombasa


October 20, 2552

Controlled by:

Office of Naval Intelligence



"The Office of Naval Intelligence (ONI) maintains a facility inside the New Mombasa city limits. Be a good neighbor, and respect the ONI security perimiter!"

ONI Alpha Site was a UNSC Office of Naval Intelligence facility located in an isolated compound within Sector 10 the city of New Mombasa, Kenya.[3] Officially, it served as the ONI's headquarters in the East African Protectorate; secretly, it was also used to aggregate data from the Forerunner artifact below it.[1]



Overhead shot of ONI Alpha Site from the ODST Mod tools
Overhead view of Alpha Site's compound.

The complex was built on an artificial island inside a walled lake. The island was accessible by a single bridge. A walled security zone encompassed most of the island. The main cubic structure occupied one end of the island on the opposite to the bridge.[3]

The main building was composed of an onyx facade.[1] It had a large shaft in its center, which connected all the way to the Superintendent's data center deep below,[4] ending at the top floor of the building. Three sides of the shaft were occupied by elevators. The elevators were accessible through the central platform of the building, suspended over the central shaft. The numerous offices in the building were accessible through the elevators. On the roof, there were several landing pads.[3]

The opposite side to the entrance on the ground floor featured open sides with walkways and balconies suspended over the pool of water below. A memorial to deceased ONI personnel was located in this area.[3]


Human-Covenant War[edit]

Main article: Human-Covenant War
The Superintendent witnessing the destruction of Alpha Site.[3]

The facility remained in UNSC hands part way through the Battle of Mombasa, despite the Covenant's efforts to breach the facility in order to obtain information on the Forerunner artifact underneath.[1] The site was first primarily defended by a New Mombasa Police Department detachment. Several hours after the Prophet of Regret's departure from the city, the police officers were joined by Orbital Drop Shock Troopers Michael "Mickey" Crespo and Taylor H. "Dutch" Miles; the troopers were separated from their squad.[3]

Officers and troopers finished preparations to demolish the access bridge as Covenant forces, including Wraiths, began to cross. The bridge's destruction forced the assault to rely on troops ferried in by Phantoms. The defenders fell back to the security zone before making a fighting withdrawal into the main structure. The destruction of the bridge and the ensuing battle led to heavy casualties on both sides.[3]

The local NMPD commander ordered the structure destroyed to deny the enemy both ONI's data and access to the Superintendent. The structure was rigged with remote-detonated charges. A police Pelican was dispatched to evacuate remaining UNSC troops. Officers and troopers held inside the structure while they waited for the transport. They finally made their way to the roof by elevator where they were picked up for the trip to NMPD headquarters. Once safely away, Crespo detonated the charges and demolished the building.[3] Six hours later, when the Rookie viewed the site from the other side of the destroyed bridge, it was still burning.[5]

During the battle, Yanme'e attacked in the elevator and were killed.[3] It was later revealed that there was a Drone hive in the tunnels below the building where the Superintendent's data center was and destroying the building woke up the whole hive, making it much harder for Dare and the Rookie to reach the data core later.[4]


Three Halo 3: ODST Firefight maps take place in or in vicinity of the base: Security Zone is located on the hill in front of the main building, Rally Point is at the entrance to the compound in Sector 10, and Alpha Site is set in the interior of the main building.

When viewing the structure during Mombasa Streets, you may notice one or two Phantoms circling above it. These will continue to do so until you leave and unload the sector.

Aside from Mombasa Streets and ONI Alpha Site, this building can also be seen in the background on the levels NMPD HQ and Coastal Highway.


List of appearances[edit]


  1. ^ a b c d e Halo: The Essential Visual Guide, page 132
  2. ^ a b Field Operations Guide FM 90-10-140
  3. ^ a b c d e f g h i Halo 3: ODST, campaign level ONI Alpha Site
  4. ^ a b Halo 3: ODST, campaign level Data Hive
  5. ^ Halo 3: ODST, campaign level Mombasa Streets