This thesis is an examination of the backgrounds of twenty-five individuals who conducted a ‘jihad’ inspired terrorist attack within the United States between the years of 2001 and 2016 to determine if terrorists use physical training camps or online training camps as the main method of training to prepare for their attacks. The debate about the existence of online training camps is beneficial to the field of terrorism study. However, the question of what constitutes an online training camp must first be answered before it can be determined if terrorists are using online training camps. This thesis proposes a comprehensive definition for the term ‘online training camp;’ in an attempt to provide an analytical basis for the examination of U.S. based terrorist training to further the academic discussion. Additionally, it is suggested from the empirical examination of U.S.-based terrorist training backgrounds that terrorists appear to be engaging in supplemental self-directed online learning in combination with physical training, rather than a complete abandonment of physical training.