This study examines the floristic diversity and threats to the peri urban forest of Ben Aknoun, Algiers, which acts as a refuge for endemic species threatened by urbanization, deforestation, overgrazing, climate change, and pollution. Located 20 km from Algiers, the 300 hectare forest has a Mediterranean climate. Two survey campaigns were conducted in April and June of 2023 and 2024, using Geographic Information Systems (GIS) to map floristic diversity and land use. The study identified six vegetation types, primarily maquis and forests. The floristic inventory recorded 167 species, including 16 introduced and 151 native species, distributed across 52 botanical families, notably Asteraceae, Apiaceae, and Fabaceae. Therophytes and hemicryptophytes dominate, indicating ecological disturbances. Fifteen chorological types are present, with Mediterranean dominance. Sixteen species are of special concern due to their rarity or endemic nature. The overall disturbance index is 45%, with Zone IV being the most affected (63%). Grazing and urbanization are the primary causes of degradation. Conserving this forest is essential for protecting its rare and endemic species. Urgent measures are required to regulate urbanization, control deforestation, and raise local awareness about the importance of biodiversity to preserve this forest for future generations and global biodiversity.