Aïn Oussera, also known as Aïn Oussara, is a city located in the Djelfa Province of Algeria. Situated approximately 200 km south of the capital city, Algiers, it serves as the administrative seat of the Aïn Oussera District. The city is positioned at the crossroads of the N1 (Trans-Saharan Highway) and the N40B highways.
The city has experienced rapid population growth since 1990, a trend attributed to its proximity to the 15 MW Es Salam nuclear reactor. It is also served by the Algerian Air Force's Aïn Oussera airfield (DAAQ). The Trans-Saharan Highway passing through the area is part of a major 2,000 km north-to-south road network connecting Algiers with Mali near Tamanrasset.