In Halo 3: ODST, the Covenant occupies the Kenyan city of New Mombasa.
New Mombasa is a major human city in East Africa and a recurring location in the Halo universe. The city is attacked during the events surrounding Halo 2, when the Covenant flagship High Charity arrives above Earth. Halo 3: ODST follows a squad of Orbital Drop Shock Troopers after a slipspace rupture scatters them across the city.
Rather than presenting the campaign as one continuous sequence, the game uses a framed investigation. The Rookie explores the darkened streets and discovers clues left by other squad members, while playable flashbacks reveal what happened to them. This structure makes New Mombasa feel like both a battlefield and a mystery setting.
New Mombasa is sometimes confused with Voi, another Kenyan location featured prominently in Halo 3. Voi is a town and industrial area south of the city, while Halo 3: ODST’s central urban environment is New Mombasa. The game’s atmosphere also distinguishes it from the brighter military settings of earlier entries.