The ability of Al Qaeda to overcome the loss of its sanctuary in 2001, as well as ISIS's success in building a quasi-state after its conquest of large swathe of territory has provoked an interest in examining the centrality of land control to these terrorist organizations and its effect on their functional dynamics. The following analysis provides a process tracing of Al Qaeda since its creation, and what became later on known as the Islamic State of Iraq and Syria, and evaluates whether they adopted a hierarchal structure when they controlled territory, and whether they operated as a network when they lacked territory. The study mainly focuses on the decision making procedures and the relationship between the leaders and members. Furthermore, it also looks into the effect of territorial control on the performance of these two terrorist organizations, and whether total territorial control which allows these groups to establish a state will increase their lethality. The findings suggests that territorial control is irrelevant to the group's decision to adopt a hierarchical or network structure, and being in total control of a territory doesn't increase the number of casualties but on the contrary, as these terrorist organizations lose territory they kill more people.