This thesis draws on concepts from terrorism, political violence and criminology literature to examine the internal variations of al-Shabaab attacks in Kenya and the significance of grievances, ideology, social identity, social networks and physical geography. Overall, the findings from this research illustrate that the threat of terrorism from a single group can vary significantly across a country according to specific regional and local conditions. This research illustrates how terrorist organisations adapt attack patterns and strategies to maximise the opportunities presented by different aspects of a country's physical geography, including urban areas, borderlands and rough terrain characterised by dense forests. This research also identifies the human and geographical channels through which cross-border terrorist activities foster domestic terrorism. In so doing, it captures the centrality of local knowledge to the perpetuation of terrorist activities. The last three empirical chapters illustrate how terrorist organisations tap into and frame context-specific grievances and conditions to foster and politicise group identity, build support and in the target selection process. The findings from this thesis underscore the importance of adopting a historical, contemporary and context-focused approach to understanding the dynamics of terrorism. They also capture the interconnection between ideology, grievances, identity, social networks, and aspects of a country’s physical geography in shaping terrorist attack and recruitment patterns. The outcome of this thesis is a methodological approach for the cross-regional study of terrorism. The elements of the proposed approach, which form the basis of the five results chapters, are summarised in the concluding chapter of this thesis.