Karantina —also known as Al Khodr or Maslakh part of the district of Medawar—is the neighborhood situated in north-eastern Beirut, bordered by the Charles Helou highway to the south, the Beirut River to the east, and the Beirut port from the west and north. Enclosed by these infrastructure, the neighborhood has effectively become an island within the city. However, Karantina has not always been severed from its urban milieu. Up until the mid-1960s, it enjoyed access to the beach and the river, and perhaps most importantly, was at a walking distance from adjacent Mar Mikhael, Hadjin and Geitawi neighborhoods. This paper focuses specifically on the Charles Helou highway. Part of a larger infrastructural project, imagined during the mandate era but only executed after the Lebanese independence, this segment of the highway reified the marginalization of Karantina within Beirut. Once a part of the urban fabric of Medawar, the highway came to materialize and reinforce the general perceptions of Karantina as the capital’s unwanted district. In the pre-Civil War era, the neighborhood was a bustling working class district with a diverse population of migrant laborers (Southerners, Syrian), refugees (Armenian, Kurdish, Palestinian), and local communities. Karantina was also part of the “poverty belt” that wrapped around Beirut at the time. But unlike the other neighborhoods of the belt, Karantina was situated within the city limits. In this paper, I argue that the Charles Helou highway was part of a larger urban policy to rid the city of unwanted populations in the name of modernization. I draw connections between the Lebanese state’s approach to the production of space and that of the French mandate era, where urban infrastructure becomes the immutable vessel for a French colonial legacy. The highway, as an irrevocable urban development, was indeed designed to definitively suffocate any future development in Karantina, and atrophy its relation to the city. The paper is based on 18 months of fieldwork, and mobilizes oral histories, archival research, and participant observation to understand the long-term implication of these state-led development of the neighborhood and its people.